diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "quote.h"
   6 #include "diff.h"
   7 #include "diffcore.h"
   8 #include "delta.h"
   9 #include "xdiff-interface.h"
  10 #include "color.h"
  11 #include "attr.h"
  12 #include "run-command.h"
  13 #include "utf8.h"
  14
  15 #ifdef NO_FAST_WORKING_DIRECTORY
  16 #define FAST_WORKING_DIRECTORY 0
  17 #else
  18 #define FAST_WORKING_DIRECTORY 1
  19 #endif
  20
  21 static int diff_detect_rename_default;
  22 static int diff_rename_limit_default = 200;
  23 static int diff_suppress_blank_empty;
  24 int diff_use_color_default = -1;
  25 static const char *external_diff_cmd_cfg;
  26 int diff_auto_refresh_index = 1;
  27 static int diff_mnemonic_prefix;
  28
  29 static char diff_colors[][COLOR_MAXLEN] = {
  30         "\033[m",       /* reset */
  31         "",             /* PLAIN (normal) */
  32         "\033[1m",      /* METAINFO (bold) */
  33         "\033[36m",     /* FRAGINFO (cyan) */
  34         "\033[31m",     /* OLD (red) */
  35         "\033[32m",     /* NEW (green) */
  36         "\033[33m",     /* COMMIT (yellow) */
  37         "\033[41m",     /* WHITESPACE (red background) */
  38 };
  39
  40 static int parse_diff_color_slot(const char *var, int ofs)
  41 {
  42         if (!strcasecmp(var+ofs, "plain"))
  43                 return DIFF_PLAIN;
  44         if (!strcasecmp(var+ofs, "meta"))
  45                 return DIFF_METAINFO;
  46         if (!strcasecmp(var+ofs, "frag"))
  47                 return DIFF_FRAGINFO;
  48         if (!strcasecmp(var+ofs, "old"))
  49                 return DIFF_FILE_OLD;
  50         if (!strcasecmp(var+ofs, "new"))
  51                 return DIFF_FILE_NEW;
  52         if (!strcasecmp(var+ofs, "commit"))
  53                 return DIFF_COMMIT;
  54         if (!strcasecmp(var+ofs, "whitespace"))
  55                 return DIFF_WHITESPACE;
  56         die("bad config variable '%s'", var);
  57 }
  58
  59 static struct ll_diff_driver {
  60         const char *name;
  61         struct ll_diff_driver *next;
  62         const char *cmd;
  63 } *user_diff, **user_diff_tail;
  64
  65 /*
  66  * Currently there is only "diff.<drivername>.command" variable;
  67  * because there are "diff.color.<slot>" variables, we are parsing
  68  * this in a bit convoluted way to allow low level diff driver
  69  * called "color".
  70  */
  71 static int parse_lldiff_command(const char *var, const char *ep, const char *value)
  72 {
  73         const char *name;
  74         int namelen;
  75         struct ll_diff_driver *drv;
  76
  77         name = var + 5;
  78         namelen = ep - name;
  79         for (drv = user_diff; drv; drv = drv->next)
  80                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
  81                         break;
  82         if (!drv) {
  83                 drv = xcalloc(1, sizeof(struct ll_diff_driver));
  84                 drv->name = xmemdupz(name, namelen);
  85                 if (!user_diff_tail)
  86                         user_diff_tail = &user_diff;
  87                 *user_diff_tail = drv;
  88                 user_diff_tail = &(drv->next);
  89         }
  90
  91         return git_config_string(&(drv->cmd), var, value);
  92 }
  93
  94 /*
  95  * 'diff.<what>.funcname' attribute can be specified in the configuration
  96  * to define a customized regexp to find the beginning of a function to
  97  * be used for hunk header lines of "diff -p" style output.
  98  */
  99 struct funcname_pattern_entry {
 100         char *name;
 101         char *pattern;
 102         int cflags;
 103 };
 104 static struct funcname_pattern_list {
 105         struct funcname_pattern_list *next;
 106         struct funcname_pattern_entry e;
 107 } *funcname_pattern_list;
 108
 109 static int parse_funcname_pattern(const char *var, const char *ep, const char *value, int cflags)
 110 {
 111         const char *name;
 112         int namelen;
 113         struct funcname_pattern_list *pp;
 114
 115         name = var + 5; /* "diff." */
 116         namelen = ep - name;
 117
 118         for (pp = funcname_pattern_list; pp; pp = pp->next)
 119                 if (!strncmp(pp->e.name, name, namelen) && !pp->e.name[namelen])
 120                         break;
 121         if (!pp) {
 122                 pp = xcalloc(1, sizeof(*pp));
 123                 pp->e.name = xmemdupz(name, namelen);
 124                 pp->next = funcname_pattern_list;
 125                 funcname_pattern_list = pp;
 126         }
 127         free(pp->e.pattern);
 128         pp->e.pattern = xstrdup(value);
 129         pp->e.cflags = cflags;
 130         return 0;
 131 }
 132
 133 /*
 134  * These are to give UI layer defaults.
 135  * The core-level commands such as git-diff-files should
 136  * never be affected by the setting of diff.renames
 137  * the user happens to have in the configuration file.
 138  */
 139 int git_diff_ui_config(const char *var, const char *value, void *cb)
 140 {
 141         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 142                 diff_use_color_default = git_config_colorbool(var, value, -1);
 143                 return 0;
 144         }
 145         if (!strcmp(var, "diff.renames")) {
 146                 if (!value)
 147                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 148                 else if (!strcasecmp(value, "copies") ||
 149                          !strcasecmp(value, "copy"))
 150                         diff_detect_rename_default = DIFF_DETECT_COPY;
 151                 else if (git_config_bool(var,value))
 152                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 153                 return 0;
 154         }
 155         if (!strcmp(var, "diff.autorefreshindex")) {
 156                 diff_auto_refresh_index = git_config_bool(var, value);
 157                 return 0;
 158         }
 159         if (!strcmp(var, "diff.mnemonicprefix")) {
 160                 diff_mnemonic_prefix = git_config_bool(var, value);
 161                 return 0;
 162         }
 163         if (!strcmp(var, "diff.external"))
 164                 return git_config_string(&external_diff_cmd_cfg, var, value);
 165         if (!prefixcmp(var, "diff.")) {
 166                 const char *ep = strrchr(var, '.');
 167
 168                 if (ep != var + 4 && !strcmp(ep, ".command"))
 169                         return parse_lldiff_command(var, ep, value);
 170         }
 171
 172         return git_diff_basic_config(var, value, cb);
 173 }
 174
 175 int git_diff_basic_config(const char *var, const char *value, void *cb)
 176 {
 177         if (!strcmp(var, "diff.renamelimit")) {
 178                 diff_rename_limit_default = git_config_int(var, value);
 179                 return 0;
 180         }
 181
 182         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 183                 int slot = parse_diff_color_slot(var, 11);
 184                 if (!value)
 185                         return config_error_nonbool(var);
 186                 color_parse(value, var, diff_colors[slot]);
 187                 return 0;
 188         }
 189
 190         /* like GNU diff's --suppress-blank-empty option  */
 191         if (!strcmp(var, "diff.suppress-blank-empty")) {
 192                 diff_suppress_blank_empty = git_config_bool(var, value);
 193                 return 0;
 194         }
 195
 196         if (!prefixcmp(var, "diff.")) {
 197                 const char *ep = strrchr(var, '.');
 198                 if (ep != var + 4) {
 199                         if (!strcmp(ep, ".funcname")) {
 200                                 if (!value)
 201                                         return config_error_nonbool(var);
 202                                 return parse_funcname_pattern(var, ep, value,
 203                                         0);
 204                         } else if (!strcmp(ep, ".xfuncname")) {
 205                                 if (!value)
 206                                         return config_error_nonbool(var);
 207                                 return parse_funcname_pattern(var, ep, value,
 208                                         REG_EXTENDED);
 209                         }
 210                 }
 211         }
 212
 213         return git_color_default_config(var, value, cb);
 214 }
 215
 216 static char *quote_two(const char *one, const char *two)
 217 {
 218         int need_one = quote_c_style(one, NULL, NULL, 1);
 219         int need_two = quote_c_style(two, NULL, NULL, 1);
 220         struct strbuf res;
 221
 222         strbuf_init(&res, 0);
 223         if (need_one + need_two) {
 224                 strbuf_addch(&res, '"');
 225                 quote_c_style(one, &res, NULL, 1);
 226                 quote_c_style(two, &res, NULL, 1);
 227                 strbuf_addch(&res, '"');
 228         } else {
 229                 strbuf_addstr(&res, one);
 230                 strbuf_addstr(&res, two);
 231         }
 232         return strbuf_detach(&res, NULL);
 233 }
 234
 235 static const char *external_diff(void)
 236 {
 237         static const char *external_diff_cmd = NULL;
 238         static int done_preparing = 0;
 239
 240         if (done_preparing)
 241                 return external_diff_cmd;
 242         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 243         if (!external_diff_cmd)
 244                 external_diff_cmd = external_diff_cmd_cfg;
 245         done_preparing = 1;
 246         return external_diff_cmd;
 247 }
 248
 249 static struct diff_tempfile {
 250         const char *name; /* filename external diff should read from */
 251         char hex[41];
 252         char mode[10];
 253         char tmp_path[PATH_MAX];
 254 } diff_temp[2];
 255
 256 static int count_lines(const char *data, int size)
 257 {
 258         int count, ch, completely_empty = 1, nl_just_seen = 0;
 259         count = 0;
 260         while (0 < size--) {
 261                 ch = *data++;
 262                 if (ch == '\n') {
 263                         count++;
 264                         nl_just_seen = 1;
 265                         completely_empty = 0;
 266                 }
 267                 else {
 268                         nl_just_seen = 0;
 269                         completely_empty = 0;
 270                 }
 271         }
 272         if (completely_empty)
 273                 return 0;
 274         if (!nl_just_seen)
 275                 count++; /* no trailing newline */
 276         return count;
 277 }
 278
 279 static void print_line_count(FILE *file, int count)
 280 {
 281         switch (count) {
 282         case 0:
 283                 fprintf(file, "0,0");
 284                 break;
 285         case 1:
 286                 fprintf(file, "1");
 287                 break;
 288         default:
 289                 fprintf(file, "1,%d", count);
 290                 break;
 291         }
 292 }
 293
 294 static void copy_file_with_prefix(FILE *file,
 295                                   int prefix, const char *data, int size,
 296                                   const char *set, const char *reset)
 297 {
 298         int ch, nl_just_seen = 1;
 299         while (0 < size--) {
 300                 ch = *data++;
 301                 if (nl_just_seen) {
 302                         fputs(set, file);
 303                         putc(prefix, file);
 304                 }
 305                 if (ch == '\n') {
 306                         nl_just_seen = 1;
 307                         fputs(reset, file);
 308                 } else
 309                         nl_just_seen = 0;
 310                 putc(ch, file);
 311         }
 312         if (!nl_just_seen)
 313                 fprintf(file, "%s\n\\ No newline at end of file\n", reset);
 314 }
 315
 316 static void emit_rewrite_diff(const char *name_a,
 317                               const char *name_b,
 318                               struct diff_filespec *one,
 319                               struct diff_filespec *two,
 320                               struct diff_options *o)
 321 {
 322         int lc_a, lc_b;
 323         int color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
 324         const char *name_a_tab, *name_b_tab;
 325         const char *metainfo = diff_get_color(color_diff, DIFF_METAINFO);
 326         const char *fraginfo = diff_get_color(color_diff, DIFF_FRAGINFO);
 327         const char *old = diff_get_color(color_diff, DIFF_FILE_OLD);
 328         const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
 329         const char *reset = diff_get_color(color_diff, DIFF_RESET);
 330         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 331         const char *a_prefix, *b_prefix;
 332
 333         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 334                 a_prefix = o->b_prefix;
 335                 b_prefix = o->a_prefix;
 336         } else {
 337                 a_prefix = o->a_prefix;
 338                 b_prefix = o->b_prefix;
 339         }
 340
 341         name_a += (*name_a == '/');
 342         name_b += (*name_b == '/');
 343         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 344         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 345
 346         strbuf_reset(&a_name);
 347         strbuf_reset(&b_name);
 348         quote_two_c_style(&a_name, a_prefix, name_a, 0);
 349         quote_two_c_style(&b_name, b_prefix, name_b, 0);
 350
 351         diff_populate_filespec(one, 0);
 352         diff_populate_filespec(two, 0);
 353         lc_a = count_lines(one->data, one->size);
 354         lc_b = count_lines(two->data, two->size);
 355         fprintf(o->file,
 356                 "%s--- %s%s%s\n%s+++ %s%s%s\n%s@@ -",
 357                 metainfo, a_name.buf, name_a_tab, reset,
 358                 metainfo, b_name.buf, name_b_tab, reset, fraginfo);
 359         print_line_count(o->file, lc_a);
 360         fprintf(o->file, " +");
 361         print_line_count(o->file, lc_b);
 362         fprintf(o->file, " @@%s\n", reset);
 363         if (lc_a)
 364                 copy_file_with_prefix(o->file, '-', one->data, one->size, old, reset);
 365         if (lc_b)
 366                 copy_file_with_prefix(o->file, '+', two->data, two->size, new, reset);
 367 }
 368
 369 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 370 {
 371         if (!DIFF_FILE_VALID(one)) {
 372                 mf->ptr = (char *)""; /* does not matter */
 373                 mf->size = 0;
 374                 return 0;
 375         }
 376         else if (diff_populate_filespec(one, 0))
 377                 return -1;
 378         mf->ptr = one->data;
 379         mf->size = one->size;
 380         return 0;
 381 }
 382
 383 struct diff_words_buffer {
 384         mmfile_t text;
 385         long alloc;
 386         long current; /* output pointer */
 387         int suppressed_newline;
 388 };
 389
 390 static void diff_words_append(char *line, unsigned long len,
 391                 struct diff_words_buffer *buffer)
 392 {
 393         if (buffer->text.size + len > buffer->alloc) {
 394                 buffer->alloc = (buffer->text.size + len) * 3 / 2;
 395                 buffer->text.ptr = xrealloc(buffer->text.ptr, buffer->alloc);
 396         }
 397         line++;
 398         len--;
 399         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 400         buffer->text.size += len;
 401 }
 402
 403 struct diff_words_data {
 404         struct diff_words_buffer minus, plus;
 405         FILE *file;
 406 };
 407
 408 static void print_word(FILE *file, struct diff_words_buffer *buffer, int len, int color,
 409                 int suppress_newline)
 410 {
 411         const char *ptr;
 412         int eol = 0;
 413
 414         if (len == 0)
 415                 return;
 416
 417         ptr  = buffer->text.ptr + buffer->current;
 418         buffer->current += len;
 419
 420         if (ptr[len - 1] == '\n') {
 421                 eol = 1;
 422                 len--;
 423         }
 424
 425         fputs(diff_get_color(1, color), file);
 426         fwrite(ptr, len, 1, file);
 427         fputs(diff_get_color(1, DIFF_RESET), file);
 428
 429         if (eol) {
 430                 if (suppress_newline)
 431                         buffer->suppressed_newline = 1;
 432                 else
 433                         putc('\n', file);
 434         }
 435 }
 436
 437 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 438 {
 439         struct diff_words_data *diff_words = priv;
 440
 441         if (diff_words->minus.suppressed_newline) {
 442                 if (line[0] != '+')
 443                         putc('\n', diff_words->file);
 444                 diff_words->minus.suppressed_newline = 0;
 445         }
 446
 447         len--;
 448         switch (line[0]) {
 449                 case '-':
 450                         print_word(diff_words->file,
 451                                    &diff_words->minus, len, DIFF_FILE_OLD, 1);
 452                         break;
 453                 case '+':
 454                         print_word(diff_words->file,
 455                                    &diff_words->plus, len, DIFF_FILE_NEW, 0);
 456                         break;
 457                 case ' ':
 458                         print_word(diff_words->file,
 459                                    &diff_words->plus, len, DIFF_PLAIN, 0);
 460                         diff_words->minus.current += len;
 461                         break;
 462         }
 463 }
 464
 465 /* this executes the word diff on the accumulated buffers */
 466 static void diff_words_show(struct diff_words_data *diff_words)
 467 {
 468         xpparam_t xpp;
 469         xdemitconf_t xecfg;
 470         xdemitcb_t ecb;
 471         mmfile_t minus, plus;
 472         int i;
 473
 474         memset(&xecfg, 0, sizeof(xecfg));
 475         minus.size = diff_words->minus.text.size;
 476         minus.ptr = xmalloc(minus.size);
 477         memcpy(minus.ptr, diff_words->minus.text.ptr, minus.size);
 478         for (i = 0; i < minus.size; i++)
 479                 if (isspace(minus.ptr[i]))
 480                         minus.ptr[i] = '\n';
 481         diff_words->minus.current = 0;
 482
 483         plus.size = diff_words->plus.text.size;
 484         plus.ptr = xmalloc(plus.size);
 485         memcpy(plus.ptr, diff_words->plus.text.ptr, plus.size);
 486         for (i = 0; i < plus.size; i++)
 487                 if (isspace(plus.ptr[i]))
 488                         plus.ptr[i] = '\n';
 489         diff_words->plus.current = 0;
 490
 491         xpp.flags = XDF_NEED_MINIMAL;
 492         xecfg.ctxlen = diff_words->minus.alloc + diff_words->plus.alloc;
 493         xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
 494                       &xpp, &xecfg, &ecb);
 495         free(minus.ptr);
 496         free(plus.ptr);
 497         diff_words->minus.text.size = diff_words->plus.text.size = 0;
 498
 499         if (diff_words->minus.suppressed_newline) {
 500                 putc('\n', diff_words->file);
 501                 diff_words->minus.suppressed_newline = 0;
 502         }
 503 }
 504
 505 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 506
 507 struct emit_callback {
 508         int nparents, color_diff;
 509         unsigned ws_rule;
 510         sane_truncate_fn truncate;
 511         const char **label_path;
 512         struct diff_words_data *diff_words;
 513         int *found_changesp;
 514         FILE *file;
 515 };
 516
 517 static void free_diff_words_data(struct emit_callback *ecbdata)
 518 {
 519         if (ecbdata->diff_words) {
 520                 /* flush buffers */
 521                 if (ecbdata->diff_words->minus.text.size ||
 522                                 ecbdata->diff_words->plus.text.size)
 523                         diff_words_show(ecbdata->diff_words);
 524
 525                 free (ecbdata->diff_words->minus.text.ptr);
 526                 free (ecbdata->diff_words->plus.text.ptr);
 527                 free(ecbdata->diff_words);
 528                 ecbdata->diff_words = NULL;
 529         }
 530 }
 531
 532 const char *diff_get_color(int diff_use_color, enum color_diff ix)
 533 {
 534         if (diff_use_color)
 535                 return diff_colors[ix];
 536         return "";
 537 }
 538
 539 static void emit_line(FILE *file, const char *set, const char *reset, const char *line, int len)
 540 {
 541         int has_trailing_newline, has_trailing_carriage_return;
 542
 543         has_trailing_newline = (len > 0 && line[len-1] == '\n');
 544         if (has_trailing_newline)
 545                 len--;
 546         has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 547         if (has_trailing_carriage_return)
 548                 len--;
 549
 550         fputs(set, file);
 551         fwrite(line, len, 1, file);
 552         fputs(reset, file);
 553         if (has_trailing_carriage_return)
 554                 fputc('\r', file);
 555         if (has_trailing_newline)
 556                 fputc('\n', file);
 557 }
 558
 559 static void emit_add_line(const char *reset, struct emit_callback *ecbdata, const char *line, int len)
 560 {
 561         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 562         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 563
 564         if (!*ws)
 565                 emit_line(ecbdata->file, set, reset, line, len);
 566         else {
 567                 /* Emit just the prefix, then the rest. */
 568                 emit_line(ecbdata->file, set, reset, line, ecbdata->nparents);
 569                 ws_check_emit(line + ecbdata->nparents,
 570                               len - ecbdata->nparents, ecbdata->ws_rule,
 571                               ecbdata->file, set, reset, ws);
 572         }
 573 }
 574
 575 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
 576 {
 577         const char *cp;
 578         unsigned long allot;
 579         size_t l = len;
 580
 581         if (ecb->truncate)
 582                 return ecb->truncate(line, len);
 583         cp = line;
 584         allot = l;
 585         while (0 < l) {
 586                 (void) utf8_width(&cp, &l);
 587                 if (!cp)
 588                         break; /* truncated in the middle? */
 589         }
 590         return allot - l;
 591 }
 592
 593 static void fn_out_consume(void *priv, char *line, unsigned long len)
 594 {
 595         int i;
 596         int color;
 597         struct emit_callback *ecbdata = priv;
 598         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
 599         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 600         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 601
 602         *(ecbdata->found_changesp) = 1;
 603
 604         if (ecbdata->label_path[0]) {
 605                 const char *name_a_tab, *name_b_tab;
 606
 607                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
 608                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
 609
 610                 fprintf(ecbdata->file, "%s--- %s%s%s\n",
 611                         meta, ecbdata->label_path[0], reset, name_a_tab);
 612                 fprintf(ecbdata->file, "%s+++ %s%s%s\n",
 613                         meta, ecbdata->label_path[1], reset, name_b_tab);
 614                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 615         }
 616
 617         if (diff_suppress_blank_empty
 618             && len == 2 && line[0] == ' ' && line[1] == '\n') {
 619                 line[0] = '\n';
 620                 len = 1;
 621         }
 622
 623         /* This is not really necessary for now because
 624          * this codepath only deals with two-way diffs.
 625          */
 626         for (i = 0; i < len && line[i] == '@'; i++)
 627                 ;
 628         if (2 <= i && i < len && line[i] == ' ') {
 629                 ecbdata->nparents = i - 1;
 630                 len = sane_truncate_line(ecbdata, line, len);
 631                 emit_line(ecbdata->file,
 632                           diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO),
 633                           reset, line, len);
 634                 if (line[len-1] != '\n')
 635                         putc('\n', ecbdata->file);
 636                 return;
 637         }
 638
 639         if (len < ecbdata->nparents) {
 640                 emit_line(ecbdata->file, reset, reset, line, len);
 641                 return;
 642         }
 643
 644         color = DIFF_PLAIN;
 645         if (ecbdata->diff_words && ecbdata->nparents != 1)
 646                 /* fall back to normal diff */
 647                 free_diff_words_data(ecbdata);
 648         if (ecbdata->diff_words) {
 649                 if (line[0] == '-') {
 650                         diff_words_append(line, len,
 651                                           &ecbdata->diff_words->minus);
 652                         return;
 653                 } else if (line[0] == '+') {
 654                         diff_words_append(line, len,
 655                                           &ecbdata->diff_words->plus);
 656                         return;
 657                 }
 658                 if (ecbdata->diff_words->minus.text.size ||
 659                     ecbdata->diff_words->plus.text.size)
 660                         diff_words_show(ecbdata->diff_words);
 661                 line++;
 662                 len--;
 663                 emit_line(ecbdata->file, plain, reset, line, len);
 664                 return;
 665         }
 666         for (i = 0; i < ecbdata->nparents && len; i++) {
 667                 if (line[i] == '-')
 668                         color = DIFF_FILE_OLD;
 669                 else if (line[i] == '+')
 670                         color = DIFF_FILE_NEW;
 671         }
 672
 673         if (color != DIFF_FILE_NEW) {
 674                 emit_line(ecbdata->file,
 675                           diff_get_color(ecbdata->color_diff, color),
 676                           reset, line, len);
 677                 return;
 678         }
 679         emit_add_line(reset, ecbdata, line, len);
 680 }
 681
 682 static char *pprint_rename(const char *a, const char *b)
 683 {
 684         const char *old = a;
 685         const char *new = b;
 686         struct strbuf name;
 687         int pfx_length, sfx_length;
 688         int len_a = strlen(a);
 689         int len_b = strlen(b);
 690         int a_midlen, b_midlen;
 691         int qlen_a = quote_c_style(a, NULL, NULL, 0);
 692         int qlen_b = quote_c_style(b, NULL, NULL, 0);
 693
 694         strbuf_init(&name, 0);
 695         if (qlen_a || qlen_b) {
 696                 quote_c_style(a, &name, NULL, 0);
 697                 strbuf_addstr(&name, " => ");
 698                 quote_c_style(b, &name, NULL, 0);
 699                 return strbuf_detach(&name, NULL);
 700         }
 701
 702         /* Find common prefix */
 703         pfx_length = 0;
 704         while (*old && *new && *old == *new) {
 705                 if (*old == '/')
 706                         pfx_length = old - a + 1;
 707                 old++;
 708                 new++;
 709         }
 710
 711         /* Find common suffix */
 712         old = a + len_a;
 713         new = b + len_b;
 714         sfx_length = 0;
 715         while (a <= old && b <= new && *old == *new) {
 716                 if (*old == '/')
 717                         sfx_length = len_a - (old - a);
 718                 old--;
 719                 new--;
 720         }
 721
 722         /*
 723          * pfx{mid-a => mid-b}sfx
 724          * {pfx-a => pfx-b}sfx
 725          * pfx{sfx-a => sfx-b}
 726          * name-a => name-b
 727          */
 728         a_midlen = len_a - pfx_length - sfx_length;
 729         b_midlen = len_b - pfx_length - sfx_length;
 730         if (a_midlen < 0)
 731                 a_midlen = 0;
 732         if (b_midlen < 0)
 733                 b_midlen = 0;
 734
 735         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
 736         if (pfx_length + sfx_length) {
 737                 strbuf_add(&name, a, pfx_length);
 738                 strbuf_addch(&name, '{');
 739         }
 740         strbuf_add(&name, a + pfx_length, a_midlen);
 741         strbuf_addstr(&name, " => ");
 742         strbuf_add(&name, b + pfx_length, b_midlen);
 743         if (pfx_length + sfx_length) {
 744                 strbuf_addch(&name, '}');
 745                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
 746         }
 747         return strbuf_detach(&name, NULL);
 748 }
 749
 750 struct diffstat_t {
 751         int nr;
 752         int alloc;
 753         struct diffstat_file {
 754                 char *from_name;
 755                 char *name;
 756                 char *print_name;
 757                 unsigned is_unmerged:1;
 758                 unsigned is_binary:1;
 759                 unsigned is_renamed:1;
 760                 unsigned int added, deleted;
 761         } **files;
 762 };
 763
 764 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 765                                           const char *name_a,
 766                                           const char *name_b)
 767 {
 768         struct diffstat_file *x;
 769         x = xcalloc(sizeof (*x), 1);
 770         if (diffstat->nr == diffstat->alloc) {
 771                 diffstat->alloc = alloc_nr(diffstat->alloc);
 772                 diffstat->files = xrealloc(diffstat->files,
 773                                 diffstat->alloc * sizeof(x));
 774         }
 775         diffstat->files[diffstat->nr++] = x;
 776         if (name_b) {
 777                 x->from_name = xstrdup(name_a);
 778                 x->name = xstrdup(name_b);
 779                 x->is_renamed = 1;
 780         }
 781         else {
 782                 x->from_name = NULL;
 783                 x->name = xstrdup(name_a);
 784         }
 785         return x;
 786 }
 787
 788 static void diffstat_consume(void *priv, char *line, unsigned long len)
 789 {
 790         struct diffstat_t *diffstat = priv;
 791         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
 792
 793         if (line[0] == '+')
 794                 x->added++;
 795         else if (line[0] == '-')
 796                 x->deleted++;
 797 }
 798
 799 const char mime_boundary_leader[] = "------------";
 800
 801 static int scale_linear(int it, int width, int max_change)
 802 {
 803         /*
 804          * make sure that at least one '-' is printed if there were deletions,
 805          * and likewise for '+'.
 806          */
 807         if (max_change < 2)
 808                 return it;
 809         return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
 810 }
 811
 812 static void show_name(FILE *file,
 813                       const char *prefix, const char *name, int len,
 814                       const char *reset, const char *set)
 815 {
 816         fprintf(file, " %s%s%-*s%s |", set, prefix, len, name, reset);
 817 }
 818
 819 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
 820 {
 821         if (cnt <= 0)
 822                 return;
 823         fprintf(file, "%s", set);
 824         while (cnt--)
 825                 putc(ch, file);
 826         fprintf(file, "%s", reset);
 827 }
 828
 829 static void fill_print_name(struct diffstat_file *file)
 830 {
 831         char *pname;
 832
 833         if (file->print_name)
 834                 return;
 835
 836         if (!file->is_renamed) {
 837                 struct strbuf buf;
 838                 strbuf_init(&buf, 0);
 839                 if (quote_c_style(file->name, &buf, NULL, 0)) {
 840                         pname = strbuf_detach(&buf, NULL);
 841                 } else {
 842                         pname = file->name;
 843                         strbuf_release(&buf);
 844                 }
 845         } else {
 846                 pname = pprint_rename(file->from_name, file->name);
 847         }
 848         file->print_name = pname;
 849 }
 850
 851 static void show_stats(struct diffstat_t* data, struct diff_options *options)
 852 {
 853         int i, len, add, del, total, adds = 0, dels = 0;
 854         int max_change = 0, max_len = 0;
 855         int total_files = data->nr;
 856         int width, name_width;
 857         const char *reset, *set, *add_c, *del_c;
 858
 859         if (data->nr == 0)
 860                 return;
 861
 862         width = options->stat_width ? options->stat_width : 80;
 863         name_width = options->stat_name_width ? options->stat_name_width : 50;
 864
 865         /* Sanity: give at least 5 columns to the graph,
 866          * but leave at least 10 columns for the name.
 867          */
 868         if (width < 25)
 869                 width = 25;
 870         if (name_width < 10)
 871                 name_width = 10;
 872         else if (width < name_width + 15)
 873                 name_width = width - 15;
 874
 875         /* Find the longest filename and max number of changes */
 876         reset = diff_get_color_opt(options, DIFF_RESET);
 877         set   = diff_get_color_opt(options, DIFF_PLAIN);
 878         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
 879         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
 880
 881         for (i = 0; i < data->nr; i++) {
 882                 struct diffstat_file *file = data->files[i];
 883                 int change = file->added + file->deleted;
 884                 fill_print_name(file);
 885                 len = strlen(file->print_name);
 886                 if (max_len < len)
 887                         max_len = len;
 888
 889                 if (file->is_binary || file->is_unmerged)
 890                         continue;
 891                 if (max_change < change)
 892                         max_change = change;
 893         }
 894
 895         /* Compute the width of the graph part;
 896          * 10 is for one blank at the beginning of the line plus
 897          * " | count " between the name and the graph.
 898          *
 899          * From here on, name_width is the width of the name area,
 900          * and width is the width of the graph area.
 901          */
 902         name_width = (name_width < max_len) ? name_width : max_len;
 903         if (width < (name_width + 10) + max_change)
 904                 width = width - (name_width + 10);
 905         else
 906                 width = max_change;
 907
 908         for (i = 0; i < data->nr; i++) {
 909                 const char *prefix = "";
 910                 char *name = data->files[i]->print_name;
 911                 int added = data->files[i]->added;
 912                 int deleted = data->files[i]->deleted;
 913                 int name_len;
 914
 915                 /*
 916                  * "scale" the filename
 917                  */
 918                 len = name_width;
 919                 name_len = strlen(name);
 920                 if (name_width < name_len) {
 921                         char *slash;
 922                         prefix = "...";
 923                         len -= 3;
 924                         name += name_len - len;
 925                         slash = strchr(name, '/');
 926                         if (slash)
 927                                 name = slash;
 928                 }
 929
 930                 if (data->files[i]->is_binary) {
 931                         show_name(options->file, prefix, name, len, reset, set);
 932                         fprintf(options->file, "  Bin ");
 933                         fprintf(options->file, "%s%d%s", del_c, deleted, reset);
 934                         fprintf(options->file, " -> ");
 935                         fprintf(options->file, "%s%d%s", add_c, added, reset);
 936                         fprintf(options->file, " bytes");
 937                         fprintf(options->file, "\n");
 938                         continue;
 939                 }
 940                 else if (data->files[i]->is_unmerged) {
 941                         show_name(options->file, prefix, name, len, reset, set);
 942                         fprintf(options->file, "  Unmerged\n");
 943                         continue;
 944                 }
 945                 else if (!data->files[i]->is_renamed &&
 946                          (added + deleted == 0)) {
 947                         total_files--;
 948                         continue;
 949                 }
 950
 951                 /*
 952                  * scale the add/delete
 953                  */
 954                 add = added;
 955                 del = deleted;
 956                 total = add + del;
 957                 adds += add;
 958                 dels += del;
 959
 960                 if (width <= max_change) {
 961                         add = scale_linear(add, width, max_change);
 962                         del = scale_linear(del, width, max_change);
 963                         total = add + del;
 964                 }
 965                 show_name(options->file, prefix, name, len, reset, set);
 966                 fprintf(options->file, "%5d%s", added + deleted,
 967                                 added + deleted ? " " : "");
 968                 show_graph(options->file, '+', add, add_c, reset);
 969                 show_graph(options->file, '-', del, del_c, reset);
 970                 fprintf(options->file, "\n");
 971         }
 972         fprintf(options->file,
 973                "%s %d files changed, %d insertions(+), %d deletions(-)%s\n",
 974                set, total_files, adds, dels, reset);
 975 }
 976
 977 static void show_shortstats(struct diffstat_t* data, struct diff_options *options)
 978 {
 979         int i, adds = 0, dels = 0, total_files = data->nr;
 980
 981         if (data->nr == 0)
 982                 return;
 983
 984         for (i = 0; i < data->nr; i++) {
 985                 if (!data->files[i]->is_binary &&
 986                     !data->files[i]->is_unmerged) {
 987                         int added = data->files[i]->added;
 988                         int deleted= data->files[i]->deleted;
 989                         if (!data->files[i]->is_renamed &&
 990                             (added + deleted == 0)) {
 991                                 total_files--;
 992                         } else {
 993                                 adds += added;
 994                                 dels += deleted;
 995                         }
 996                 }
 997         }
 998         fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
 999                total_files, adds, dels);
1000 }
1001
1002 static void show_numstat(struct diffstat_t* data, struct diff_options *options)
1003 {
1004         int i;
1005
1006         if (data->nr == 0)
1007                 return;
1008
1009         for (i = 0; i < data->nr; i++) {
1010                 struct diffstat_file *file = data->files[i];
1011
1012                 if (file->is_binary)
1013                         fprintf(options->file, "-\t-\t");
1014                 else
1015                         fprintf(options->file,
1016                                 "%d\t%d\t", file->added, file->deleted);
1017                 if (options->line_termination) {
1018                         fill_print_name(file);
1019                         if (!file->is_renamed)
1020                                 write_name_quoted(file->name, options->file,
1021                                                   options->line_termination);
1022                         else {
1023                                 fputs(file->print_name, options->file);
1024                                 putc(options->line_termination, options->file);
1025                         }
1026                 } else {
1027                         if (file->is_renamed) {
1028                                 putc('\0', options->file);
1029                                 write_name_quoted(file->from_name, options->file, '\0');
1030                         }
1031                         write_name_quoted(file->name, options->file, '\0');
1032                 }
1033         }
1034 }
1035
1036 struct dirstat_file {
1037         const char *name;
1038         unsigned long changed;
1039 };
1040
1041 struct dirstat_dir {
1042         struct dirstat_file *files;
1043         int alloc, nr, percent, cumulative;
1044 };
1045
1046 static long gather_dirstat(FILE *file, struct dirstat_dir *dir, unsigned long changed, const char *base, int baselen)
1047 {
1048         unsigned long this_dir = 0;
1049         unsigned int sources = 0;
1050
1051         while (dir->nr) {
1052                 struct dirstat_file *f = dir->files;
1053                 int namelen = strlen(f->name);
1054                 unsigned long this;
1055                 char *slash;
1056
1057                 if (namelen < baselen)
1058                         break;
1059                 if (memcmp(f->name, base, baselen))
1060                         break;
1061                 slash = strchr(f->name + baselen, '/');
1062                 if (slash) {
1063                         int newbaselen = slash + 1 - f->name;
1064                         this = gather_dirstat(file, dir, changed, f->name, newbaselen);
1065                         sources++;
1066                 } else {
1067                         this = f->changed;
1068                         dir->files++;
1069                         dir->nr--;
1070                         sources += 2;
1071                 }
1072                 this_dir += this;
1073         }
1074
1075         /*
1076          * We don't report dirstat's for
1077          *  - the top level
1078          *  - or cases where everything came from a single directory
1079          *    under this directory (sources == 1).
1080          */
1081         if (baselen && sources != 1) {
1082                 int permille = this_dir * 1000 / changed;
1083                 if (permille) {
1084                         int percent = permille / 10;
1085                         if (percent >= dir->percent) {
1086                                 fprintf(file, "%4d.%01d%% %.*s\n", percent, permille % 10, baselen, base);
1087                                 if (!dir->cumulative)
1088                                         return 0;
1089                         }
1090                 }
1091         }
1092         return this_dir;
1093 }
1094
1095 static int dirstat_compare(const void *_a, const void *_b)
1096 {
1097         const struct dirstat_file *a = _a;
1098         const struct dirstat_file *b = _b;
1099         return strcmp(a->name, b->name);
1100 }
1101
1102 static void show_dirstat(struct diff_options *options)
1103 {
1104         int i;
1105         unsigned long changed;
1106         struct dirstat_dir dir;
1107         struct diff_queue_struct *q = &diff_queued_diff;
1108
1109         dir.files = NULL;
1110         dir.alloc = 0;
1111         dir.nr = 0;
1112         dir.percent = options->dirstat_percent;
1113         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1114
1115         changed = 0;
1116         for (i = 0; i < q->nr; i++) {
1117                 struct diff_filepair *p = q->queue[i];
1118                 const char *name;
1119                 unsigned long copied, added, damage;
1120
1121                 name = p->one->path ? p->one->path : p->two->path;
1122
1123                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1124                         diff_populate_filespec(p->one, 0);
1125                         diff_populate_filespec(p->two, 0);
1126                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1127                                                &copied, &added);
1128                         diff_free_filespec_data(p->one);
1129                         diff_free_filespec_data(p->two);
1130                 } else if (DIFF_FILE_VALID(p->one)) {
1131                         diff_populate_filespec(p->one, 1);
1132                         copied = added = 0;
1133                         diff_free_filespec_data(p->one);
1134                 } else if (DIFF_FILE_VALID(p->two)) {
1135                         diff_populate_filespec(p->two, 1);
1136                         copied = 0;
1137                         added = p->two->size;
1138                         diff_free_filespec_data(p->two);
1139                 } else
1140                         continue;
1141
1142                 /*
1143                  * Original minus copied is the removed material,
1144                  * added is the new material.  They are both damages
1145                  * made to the preimage. In --dirstat-by-file mode, count
1146                  * damaged files, not damaged lines. This is done by
1147                  * counting only a single damaged line per file.
1148                  */
1149                 damage = (p->one->size - copied) + added;
1150                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE) && damage > 0)
1151                         damage = 1;
1152
1153                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1154                 dir.files[dir.nr].name = name;
1155                 dir.files[dir.nr].changed = damage;
1156                 changed += damage;
1157                 dir.nr++;
1158         }
1159
1160         /* This can happen even with many files, if everything was renames */
1161         if (!changed)
1162                 return;
1163
1164         /* Show all directories with more than x% of the changes */
1165         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1166         gather_dirstat(options->file, &dir, changed, "", 0);
1167 }
1168
1169 static void free_diffstat_info(struct diffstat_t *diffstat)
1170 {
1171         int i;
1172         for (i = 0; i < diffstat->nr; i++) {
1173                 struct diffstat_file *f = diffstat->files[i];
1174                 if (f->name != f->print_name)
1175                         free(f->print_name);
1176                 free(f->name);
1177                 free(f->from_name);
1178                 free(f);
1179         }
1180         free(diffstat->files);
1181 }
1182
1183 struct checkdiff_t {
1184         const char *filename;
1185         int lineno;
1186         struct diff_options *o;
1187         unsigned ws_rule;
1188         unsigned status;
1189         int trailing_blanks_start;
1190 };
1191
1192 static int is_conflict_marker(const char *line, unsigned long len)
1193 {
1194         char firstchar;
1195         int cnt;
1196
1197         if (len < 8)
1198                 return 0;
1199         firstchar = line[0];
1200         switch (firstchar) {
1201         case '=': case '>': case '<':
1202                 break;
1203         default:
1204                 return 0;
1205         }
1206         for (cnt = 1; cnt < 7; cnt++)
1207                 if (line[cnt] != firstchar)
1208                         return 0;
1209         /* line[0] thru line[6] are same as firstchar */
1210         if (firstchar == '=') {
1211                 /* divider between ours and theirs? */
1212                 if (len != 8 || line[7] != '\n')
1213                         return 0;
1214         } else if (len < 8 || !isspace(line[7])) {
1215                 /* not divider before ours nor after theirs */
1216                 return 0;
1217         }
1218         return 1;
1219 }
1220
1221 static void checkdiff_consume(void *priv, char *line, unsigned long len)
1222 {
1223         struct checkdiff_t *data = priv;
1224         int color_diff = DIFF_OPT_TST(data->o, COLOR_DIFF);
1225         const char *ws = diff_get_color(color_diff, DIFF_WHITESPACE);
1226         const char *reset = diff_get_color(color_diff, DIFF_RESET);
1227         const char *set = diff_get_color(color_diff, DIFF_FILE_NEW);
1228         char *err;
1229
1230         if (line[0] == '+') {
1231                 unsigned bad;
1232                 data->lineno++;
1233                 if (!ws_blank_line(line + 1, len - 1, data->ws_rule))
1234                         data->trailing_blanks_start = 0;
1235                 else if (!data->trailing_blanks_start)
1236                         data->trailing_blanks_start = data->lineno;
1237                 if (is_conflict_marker(line + 1, len - 1)) {
1238                         data->status |= 1;
1239                         fprintf(data->o->file,
1240                                 "%s:%d: leftover conflict marker\n",
1241                                 data->filename, data->lineno);
1242                 }
1243                 bad = ws_check(line + 1, len - 1, data->ws_rule);
1244                 if (!bad)
1245                         return;
1246                 data->status |= bad;
1247                 err = whitespace_error_string(bad);
1248                 fprintf(data->o->file, "%s:%d: %s.\n",
1249                         data->filename, data->lineno, err);
1250                 free(err);
1251                 emit_line(data->o->file, set, reset, line, 1);
1252                 ws_check_emit(line + 1, len - 1, data->ws_rule,
1253                               data->o->file, set, reset, ws);
1254         } else if (line[0] == ' ') {
1255                 data->lineno++;
1256                 data->trailing_blanks_start = 0;
1257         } else if (line[0] == '@') {
1258                 char *plus = strchr(line, '+');
1259                 if (plus)
1260                         data->lineno = strtol(plus, NULL, 10) - 1;
1261                 else
1262                         die("invalid diff");
1263                 data->trailing_blanks_start = 0;
1264         }
1265 }
1266
1267 static unsigned char *deflate_it(char *data,
1268                                  unsigned long size,
1269                                  unsigned long *result_size)
1270 {
1271         int bound;
1272         unsigned char *deflated;
1273         z_stream stream;
1274
1275         memset(&stream, 0, sizeof(stream));
1276         deflateInit(&stream, zlib_compression_level);
1277         bound = deflateBound(&stream, size);
1278         deflated = xmalloc(bound);
1279         stream.next_out = deflated;
1280         stream.avail_out = bound;
1281
1282         stream.next_in = (unsigned char *)data;
1283         stream.avail_in = size;
1284         while (deflate(&stream, Z_FINISH) == Z_OK)
1285                 ; /* nothing */
1286         deflateEnd(&stream);
1287         *result_size = stream.total_out;
1288         return deflated;
1289 }
1290
1291 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two)
1292 {
1293         void *cp;
1294         void *delta;
1295         void *deflated;
1296         void *data;
1297         unsigned long orig_size;
1298         unsigned long delta_size;
1299         unsigned long deflate_size;
1300         unsigned long data_size;
1301
1302         /* We could do deflated delta, or we could do just deflated two,
1303          * whichever is smaller.
1304          */
1305         delta = NULL;
1306         deflated = deflate_it(two->ptr, two->size, &deflate_size);
1307         if (one->size && two->size) {
1308                 delta = diff_delta(one->ptr, one->size,
1309                                    two->ptr, two->size,
1310                                    &delta_size, deflate_size);
1311                 if (delta) {
1312                         void *to_free = delta;
1313                         orig_size = delta_size;
1314                         delta = deflate_it(delta, delta_size, &delta_size);
1315                         free(to_free);
1316                 }
1317         }
1318
1319         if (delta && delta_size < deflate_size) {
1320                 fprintf(file, "delta %lu\n", orig_size);
1321                 free(deflated);
1322                 data = delta;
1323                 data_size = delta_size;
1324         }
1325         else {
1326                 fprintf(file, "literal %lu\n", two->size);
1327                 free(delta);
1328                 data = deflated;
1329                 data_size = deflate_size;
1330         }
1331
1332         /* emit data encoded in base85 */
1333         cp = data;
1334         while (data_size) {
1335                 int bytes = (52 < data_size) ? 52 : data_size;
1336                 char line[70];
1337                 data_size -= bytes;
1338                 if (bytes <= 26)
1339                         line[0] = bytes + 'A' - 1;
1340                 else
1341                         line[0] = bytes - 26 + 'a' - 1;
1342                 encode_85(line + 1, cp, bytes);
1343                 cp = (char *) cp + bytes;
1344                 fputs(line, file);
1345                 fputc('\n', file);
1346         }
1347         fprintf(file, "\n");
1348         free(data);
1349 }
1350
1351 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two)
1352 {
1353         fprintf(file, "GIT binary patch\n");
1354         emit_binary_diff_body(file, one, two);
1355         emit_binary_diff_body(file, two, one);
1356 }
1357
1358 static void setup_diff_attr_check(struct git_attr_check *check)
1359 {
1360         static struct git_attr *attr_diff;
1361
1362         if (!attr_diff) {
1363                 attr_diff = git_attr("diff", 4);
1364         }
1365         check[0].attr = attr_diff;
1366 }
1367
1368 static void diff_filespec_check_attr(struct diff_filespec *one)
1369 {
1370         struct git_attr_check attr_diff_check;
1371         int check_from_data = 0;
1372
1373         if (one->checked_attr)
1374                 return;
1375
1376         setup_diff_attr_check(&attr_diff_check);
1377         one->is_binary = 0;
1378         one->funcname_pattern_ident = NULL;
1379
1380         if (!git_checkattr(one->path, 1, &attr_diff_check)) {
1381                 const char *value;
1382
1383                 /* binaryness */
1384                 value = attr_diff_check.value;
1385                 if (ATTR_TRUE(value))
1386                         ;
1387                 else if (ATTR_FALSE(value))
1388                         one->is_binary = 1;
1389                 else
1390                         check_from_data = 1;
1391
1392                 /* funcname pattern ident */
1393                 if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
1394                         ;
1395                 else
1396                         one->funcname_pattern_ident = value;
1397         }
1398
1399         if (check_from_data) {
1400                 if (!one->data && DIFF_FILE_VALID(one))
1401                         diff_populate_filespec(one, 0);
1402
1403                 if (one->data)
1404                         one->is_binary = buffer_is_binary(one->data, one->size);
1405         }
1406 }
1407
1408 int diff_filespec_is_binary(struct diff_filespec *one)
1409 {
1410         diff_filespec_check_attr(one);
1411         return one->is_binary;
1412 }
1413
1414 static const struct funcname_pattern_entry *funcname_pattern(const char *ident)
1415 {
1416         struct funcname_pattern_list *pp;
1417
1418         for (pp = funcname_pattern_list; pp; pp = pp->next)
1419                 if (!strcmp(ident, pp->e.name))
1420                         return &pp->e;
1421         return NULL;
1422 }
1423
1424 static const struct funcname_pattern_entry builtin_funcname_pattern[] = {
1425         { "bibtex", "(@[a-zA-Z]{1,}[ \t]*\\{{0,1}[ \t]*[^ \t\"@',\\#}{~%]*).*$",
1426           REG_EXTENDED },
1427         { "html", "^[ \t]*(<[Hh][1-6][ \t].*>.*)$", REG_EXTENDED },
1428         { "java",
1429           "!^[ \t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)\n"
1430           "^[ \t]*(([ \t]*[A-Za-z_][A-Za-z_0-9]*){2,}[ \t]*\\([^;]*)$",
1431           REG_EXTENDED },
1432         { "pascal",
1433           "^((procedure|function|constructor|destructor|interface|"
1434                 "implementation|initialization|finalization)[ \t]*.*)$"
1435           "\n"
1436           "^(.*=[ \t]*(class|record).*)$",
1437           REG_EXTENDED },
1438         { "php", "^[\t ]*((function|class).*)", REG_EXTENDED },
1439         { "python", "^[ \t]*((class|def)[ \t].*)$", REG_EXTENDED },
1440         { "ruby", "^[ \t]*((class|module|def)[ \t].*)$",
1441           REG_EXTENDED },
1442         { "tex",
1443           "^(\\\\((sub)*section|chapter|part)\\*{0,1}\\{.*)$",
1444           REG_EXTENDED },
1445 };
1446
1447 static const struct funcname_pattern_entry *diff_funcname_pattern(struct diff_filespec *one)
1448 {
1449         const char *ident;
1450         const struct funcname_pattern_entry *pe;
1451         int i;
1452
1453         diff_filespec_check_attr(one);
1454         ident = one->funcname_pattern_ident;
1455
1456         if (!ident)
1457                 /*
1458                  * If the config file has "funcname.default" defined, that
1459                  * regexp is used; otherwise NULL is returned and xemit uses
1460                  * the built-in default.
1461                  */
1462                 return funcname_pattern("default");
1463
1464         /* Look up custom "funcname.$ident" regexp from config. */
1465         pe = funcname_pattern(ident);
1466         if (pe)
1467                 return pe;
1468
1469         /*
1470          * And define built-in fallback patterns here.  Note that
1471          * these can be overridden by the user's config settings.
1472          */
1473         for (i = 0; i < ARRAY_SIZE(builtin_funcname_pattern); i++)
1474                 if (!strcmp(ident, builtin_funcname_pattern[i].name))
1475                         return &builtin_funcname_pattern[i];
1476
1477         return NULL;
1478 }
1479
1480 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
1481 {
1482         if (!options->a_prefix)
1483                 options->a_prefix = a;
1484         if (!options->b_prefix)
1485                 options->b_prefix = b;
1486 }
1487
1488 static void builtin_diff(const char *name_a,
1489                          const char *name_b,
1490                          struct diff_filespec *one,
1491                          struct diff_filespec *two,
1492                          const char *xfrm_msg,
1493                          struct diff_options *o,
1494                          int complete_rewrite)
1495 {
1496         mmfile_t mf1, mf2;
1497         const char *lbl[2];
1498         char *a_one, *b_two;
1499         const char *set = diff_get_color_opt(o, DIFF_METAINFO);
1500         const char *reset = diff_get_color_opt(o, DIFF_RESET);
1501         const char *a_prefix, *b_prefix;
1502
1503         diff_set_mnemonic_prefix(o, "a/", "b/");
1504         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
1505                 a_prefix = o->b_prefix;
1506                 b_prefix = o->a_prefix;
1507         } else {
1508                 a_prefix = o->a_prefix;
1509                 b_prefix = o->b_prefix;
1510         }
1511
1512         /* Never use a non-valid filename anywhere if at all possible */
1513         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
1514         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
1515
1516         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
1517         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
1518         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
1519         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
1520         fprintf(o->file, "%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
1521         if (lbl[0][0] == '/') {
1522                 /* /dev/null */
1523                 fprintf(o->file, "%snew file mode %06o%s\n", set, two->mode, reset);
1524                 if (xfrm_msg && xfrm_msg[0])
1525                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1526         }
1527         else if (lbl[1][0] == '/') {
1528                 fprintf(o->file, "%sdeleted file mode %06o%s\n", set, one->mode, reset);
1529                 if (xfrm_msg && xfrm_msg[0])
1530                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1531         }
1532         else {
1533                 if (one->mode != two->mode) {
1534                         fprintf(o->file, "%sold mode %06o%s\n", set, one->mode, reset);
1535                         fprintf(o->file, "%snew mode %06o%s\n", set, two->mode, reset);
1536                 }
1537                 if (xfrm_msg && xfrm_msg[0])
1538                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1539                 /*
1540                  * we do not run diff between different kind
1541                  * of objects.
1542                  */
1543                 if ((one->mode ^ two->mode) & S_IFMT)
1544                         goto free_ab_and_return;
1545                 if (complete_rewrite) {
1546                         emit_rewrite_diff(name_a, name_b, one, two, o);
1547                         o->found_changes = 1;
1548                         goto free_ab_and_return;
1549                 }
1550         }
1551
1552         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1553                 die("unable to read files to diff");
1554
1555         if (!DIFF_OPT_TST(o, TEXT) &&
1556             (diff_filespec_is_binary(one) || diff_filespec_is_binary(two))) {
1557                 /* Quite common confusing case */
1558                 if (mf1.size == mf2.size &&
1559                     !memcmp(mf1.ptr, mf2.ptr, mf1.size))
1560                         goto free_ab_and_return;
1561                 if (DIFF_OPT_TST(o, BINARY))
1562                         emit_binary_diff(o->file, &mf1, &mf2);
1563                 else
1564                         fprintf(o->file, "Binary files %s and %s differ\n",
1565                                 lbl[0], lbl[1]);
1566                 o->found_changes = 1;
1567         }
1568         else {
1569                 /* Crazy xdl interfaces.. */
1570                 const char *diffopts = getenv("GIT_DIFF_OPTS");
1571                 xpparam_t xpp;
1572                 xdemitconf_t xecfg;
1573                 xdemitcb_t ecb;
1574                 struct emit_callback ecbdata;
1575                 const struct funcname_pattern_entry *pe;
1576
1577                 pe = diff_funcname_pattern(one);
1578                 if (!pe)
1579                         pe = diff_funcname_pattern(two);
1580
1581                 memset(&xecfg, 0, sizeof(xecfg));
1582                 memset(&ecbdata, 0, sizeof(ecbdata));
1583                 ecbdata.label_path = lbl;
1584                 ecbdata.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
1585                 ecbdata.found_changesp = &o->found_changes;
1586                 ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
1587                 ecbdata.file = o->file;
1588                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1589                 xecfg.ctxlen = o->context;
1590                 xecfg.flags = XDL_EMIT_FUNCNAMES;
1591                 if (pe)
1592                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
1593                 if (!diffopts)
1594                         ;
1595                 else if (!prefixcmp(diffopts, "--unified="))
1596                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
1597                 else if (!prefixcmp(diffopts, "-u"))
1598                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
1599                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS)) {
1600                         ecbdata.diff_words =
1601                                 xcalloc(1, sizeof(struct diff_words_data));
1602                         ecbdata.diff_words->file = o->file;
1603                 }
1604                 xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
1605                               &xpp, &xecfg, &ecb);
1606                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS))
1607                         free_diff_words_data(&ecbdata);
1608         }
1609
1610  free_ab_and_return:
1611         diff_free_filespec_data(one);
1612         diff_free_filespec_data(two);
1613         free(a_one);
1614         free(b_two);
1615         return;
1616 }
1617
1618 static void builtin_diffstat(const char *name_a, const char *name_b,
1619                              struct diff_filespec *one,
1620                              struct diff_filespec *two,
1621                              struct diffstat_t *diffstat,
1622                              struct diff_options *o,
1623                              int complete_rewrite)
1624 {
1625         mmfile_t mf1, mf2;
1626         struct diffstat_file *data;
1627
1628         data = diffstat_add(diffstat, name_a, name_b);
1629
1630         if (!one || !two) {
1631                 data->is_unmerged = 1;
1632                 return;
1633         }
1634         if (complete_rewrite) {
1635                 diff_populate_filespec(one, 0);
1636                 diff_populate_filespec(two, 0);
1637                 data->deleted = count_lines(one->data, one->size);
1638                 data->added = count_lines(two->data, two->size);
1639                 goto free_and_return;
1640         }
1641         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1642                 die("unable to read files to diff");
1643
1644         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
1645                 data->is_binary = 1;
1646                 data->added = mf2.size;
1647                 data->deleted = mf1.size;
1648         } else {
1649                 /* Crazy xdl interfaces.. */
1650                 xpparam_t xpp;
1651                 xdemitconf_t xecfg;
1652                 xdemitcb_t ecb;
1653
1654                 memset(&xecfg, 0, sizeof(xecfg));
1655                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1656                 xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
1657                               &xpp, &xecfg, &ecb);
1658         }
1659
1660  free_and_return:
1661         diff_free_filespec_data(one);
1662         diff_free_filespec_data(two);
1663 }
1664
1665 static void builtin_checkdiff(const char *name_a, const char *name_b,
1666                               const char *attr_path,
1667                               struct diff_filespec *one,
1668                               struct diff_filespec *two,
1669                               struct diff_options *o)
1670 {
1671         mmfile_t mf1, mf2;
1672         struct checkdiff_t data;
1673
1674         if (!two)
1675                 return;
1676
1677         memset(&data, 0, sizeof(data));
1678         data.filename = name_b ? name_b : name_a;
1679         data.lineno = 0;
1680         data.o = o;
1681         data.ws_rule = whitespace_rule(attr_path);
1682
1683         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1684                 die("unable to read files to diff");
1685
1686         /*
1687          * All the other codepaths check both sides, but not checking
1688          * the "old" side here is deliberate.  We are checking the newly
1689          * introduced changes, and as long as the "new" side is text, we
1690          * can and should check what it introduces.
1691          */
1692         if (diff_filespec_is_binary(two))
1693                 goto free_and_return;
1694         else {
1695                 /* Crazy xdl interfaces.. */
1696                 xpparam_t xpp;
1697                 xdemitconf_t xecfg;
1698                 xdemitcb_t ecb;
1699
1700                 memset(&xecfg, 0, sizeof(xecfg));
1701                 xecfg.ctxlen = 1; /* at least one context line */
1702                 xpp.flags = XDF_NEED_MINIMAL;
1703                 xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
1704                               &xpp, &xecfg, &ecb);
1705
1706                 if ((data.ws_rule & WS_TRAILING_SPACE) &&
1707                     data.trailing_blanks_start) {
1708                         fprintf(o->file, "%s:%d: ends with blank lines.\n",
1709                                 data.filename, data.trailing_blanks_start);
1710                         data.status = 1; /* report errors */
1711                 }
1712         }
1713  free_and_return:
1714         diff_free_filespec_data(one);
1715         diff_free_filespec_data(two);
1716         if (data.status)
1717                 DIFF_OPT_SET(o, CHECK_FAILED);
1718 }
1719
1720 struct diff_filespec *alloc_filespec(const char *path)
1721 {
1722         int namelen = strlen(path);
1723         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
1724
1725         memset(spec, 0, sizeof(*spec));
1726         spec->path = (char *)(spec + 1);
1727         memcpy(spec->path, path, namelen+1);
1728         spec->count = 1;
1729         return spec;
1730 }
1731
1732 void free_filespec(struct diff_filespec *spec)
1733 {
1734         if (!--spec->count) {
1735                 diff_free_filespec_data(spec);
1736                 free(spec);
1737         }
1738 }
1739
1740 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
1741                    unsigned short mode)
1742 {
1743         if (mode) {
1744                 spec->mode = canon_mode(mode);
1745                 hashcpy(spec->sha1, sha1);
1746                 spec->sha1_valid = !is_null_sha1(sha1);
1747         }
1748 }
1749
1750 /*
1751  * Given a name and sha1 pair, if the index tells us the file in
1752  * the work tree has that object contents, return true, so that
1753  * prepare_temp_file() does not have to inflate and extract.
1754  */
1755 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
1756 {
1757         struct cache_entry *ce;
1758         struct stat st;
1759         int pos, len;
1760
1761         /* We do not read the cache ourselves here, because the
1762          * benchmark with my previous version that always reads cache
1763          * shows that it makes things worse for diff-tree comparing
1764          * two linux-2.6 kernel trees in an already checked out work
1765          * tree.  This is because most diff-tree comparisons deal with
1766          * only a small number of files, while reading the cache is
1767          * expensive for a large project, and its cost outweighs the
1768          * savings we get by not inflating the object to a temporary
1769          * file.  Practically, this code only helps when we are used
1770          * by diff-cache --cached, which does read the cache before
1771          * calling us.
1772          */
1773         if (!active_cache)
1774                 return 0;
1775
1776         /* We want to avoid the working directory if our caller
1777          * doesn't need the data in a normal file, this system
1778          * is rather slow with its stat/open/mmap/close syscalls,
1779          * and the object is contained in a pack file.  The pack
1780          * is probably already open and will be faster to obtain
1781          * the data through than the working directory.  Loose
1782          * objects however would tend to be slower as they need
1783          * to be individually opened and inflated.
1784          */
1785         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1, NULL))
1786                 return 0;
1787
1788         len = strlen(name);
1789         pos = cache_name_pos(name, len);
1790         if (pos < 0)
1791                 return 0;
1792         ce = active_cache[pos];
1793
1794         /*
1795          * This is not the sha1 we are looking for, or
1796          * unreusable because it is not a regular file.
1797          */
1798         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
1799                 return 0;
1800
1801         /*
1802          * If ce matches the file in the work tree, we can reuse it.
1803          */
1804         if (ce_uptodate(ce) ||
1805             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
1806                 return 1;
1807
1808         return 0;
1809 }
1810
1811 static int populate_from_stdin(struct diff_filespec *s)
1812 {
1813         struct strbuf buf;
1814         size_t size = 0;
1815
1816         strbuf_init(&buf, 0);
1817         if (strbuf_read(&buf, 0, 0) < 0)
1818                 return error("error while reading from stdin %s",
1819                                      strerror(errno));
1820
1821         s->should_munmap = 0;
1822         s->data = strbuf_detach(&buf, &size);
1823         s->size = size;
1824         s->should_free = 1;
1825         return 0;
1826 }
1827
1828 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
1829 {
1830         int len;
1831         char *data = xmalloc(100);
1832         len = snprintf(data, 100,
1833                 "Subproject commit %s\n", sha1_to_hex(s->sha1));
1834         s->data = data;
1835         s->size = len;
1836         s->should_free = 1;
1837         if (size_only) {
1838                 s->data = NULL;
1839                 free(data);
1840         }
1841         return 0;
1842 }
1843
1844 /*
1845  * While doing rename detection and pickaxe operation, we may need to
1846  * grab the data for the blob (or file) for our own in-core comparison.
1847  * diff_filespec has data and size fields for this purpose.
1848  */
1849 int diff_populate_filespec(struct diff_filespec *s, int size_only)
1850 {
1851         int err = 0;
1852         if (!DIFF_FILE_VALID(s))
1853                 die("internal error: asking to populate invalid file.");
1854         if (S_ISDIR(s->mode))
1855                 return -1;
1856
1857         if (s->data)
1858                 return 0;
1859
1860         if (size_only && 0 < s->size)
1861                 return 0;
1862
1863         if (S_ISGITLINK(s->mode))
1864                 return diff_populate_gitlink(s, size_only);
1865
1866         if (!s->sha1_valid ||
1867             reuse_worktree_file(s->path, s->sha1, 0)) {
1868                 struct strbuf buf;
1869                 struct stat st;
1870                 int fd;
1871
1872                 if (!strcmp(s->path, "-"))
1873                         return populate_from_stdin(s);
1874
1875                 if (lstat(s->path, &st) < 0) {
1876                         if (errno == ENOENT) {
1877                         err_empty:
1878                                 err = -1;
1879                         empty:
1880                                 s->data = (char *)"";
1881                                 s->size = 0;
1882                                 return err;
1883                         }
1884                 }
1885                 s->size = xsize_t(st.st_size);
1886                 if (!s->size)
1887                         goto empty;
1888                 if (size_only)
1889                         return 0;
1890                 if (S_ISLNK(st.st_mode)) {
1891                         int ret;
1892                         s->data = xmalloc(s->size);
1893                         s->should_free = 1;
1894                         ret = readlink(s->path, s->data, s->size);
1895                         if (ret < 0) {
1896                                 free(s->data);
1897                                 goto err_empty;
1898                         }
1899                         return 0;
1900                 }
1901                 fd = open(s->path, O_RDONLY);
1902                 if (fd < 0)
1903                         goto err_empty;
1904                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
1905                 close(fd);
1906                 s->should_munmap = 1;
1907
1908                 /*
1909                  * Convert from working tree format to canonical git format
1910                  */
1911                 strbuf_init(&buf, 0);
1912                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
1913                         size_t size = 0;
1914                         munmap(s->data, s->size);
1915                         s->should_munmap = 0;
1916                         s->data = strbuf_detach(&buf, &size);
1917                         s->size = size;
1918                         s->should_free = 1;
1919                 }
1920         }
1921         else {
1922                 enum object_type type;
1923                 if (size_only)
1924                         type = sha1_object_info(s->sha1, &s->size);
1925                 else {
1926                         s->data = read_sha1_file(s->sha1, &type, &s->size);
1927                         s->should_free = 1;
1928                 }
1929         }
1930         return 0;
1931 }
1932
1933 void diff_free_filespec_blob(struct diff_filespec *s)
1934 {
1935         if (s->should_free)
1936                 free(s->data);
1937         else if (s->should_munmap)
1938                 munmap(s->data, s->size);
1939
1940         if (s->should_free || s->should_munmap) {
1941                 s->should_free = s->should_munmap = 0;
1942                 s->data = NULL;
1943         }
1944 }
1945
1946 void diff_free_filespec_data(struct diff_filespec *s)
1947 {
1948         diff_free_filespec_blob(s);
1949         free(s->cnt_data);
1950         s->cnt_data = NULL;
1951 }
1952
1953 static void prep_temp_blob(struct diff_tempfile *temp,
1954                            void *blob,
1955                            unsigned long size,
1956                            const unsigned char *sha1,
1957                            int mode)
1958 {
1959         int fd;
1960
1961         fd = git_mkstemp(temp->tmp_path, PATH_MAX, ".diff_XXXXXX");
1962         if (fd < 0)
1963                 die("unable to create temp-file: %s", strerror(errno));
1964         if (write_in_full(fd, blob, size) != size)
1965                 die("unable to write temp-file");
1966         close(fd);
1967         temp->name = temp->tmp_path;
1968         strcpy(temp->hex, sha1_to_hex(sha1));
1969         temp->hex[40] = 0;
1970         sprintf(temp->mode, "%06o", mode);
1971 }
1972
1973 static void prepare_temp_file(const char *name,
1974                               struct diff_tempfile *temp,
1975                               struct diff_filespec *one)
1976 {
1977         if (!DIFF_FILE_VALID(one)) {
1978         not_a_valid_file:
1979                 /* A '-' entry produces this for file-2, and
1980                  * a '+' entry produces this for file-1.
1981                  */
1982                 temp->name = "/dev/null";
1983                 strcpy(temp->hex, ".");
1984                 strcpy(temp->mode, ".");
1985                 return;
1986         }
1987
1988         if (!one->sha1_valid ||
1989             reuse_worktree_file(name, one->sha1, 1)) {
1990                 struct stat st;
1991                 if (lstat(name, &st) < 0) {
1992                         if (errno == ENOENT)
1993                                 goto not_a_valid_file;
1994                         die("stat(%s): %s", name, strerror(errno));
1995                 }
1996                 if (S_ISLNK(st.st_mode)) {
1997                         int ret;
1998                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
1999                         size_t sz = xsize_t(st.st_size);
2000                         if (sizeof(buf) <= st.st_size)
2001                                 die("symlink too long: %s", name);
2002                         ret = readlink(name, buf, sz);
2003                         if (ret < 0)
2004                                 die("readlink(%s)", name);
2005                         prep_temp_blob(temp, buf, sz,
2006                                        (one->sha1_valid ?
2007                                         one->sha1 : null_sha1),
2008                                        (one->sha1_valid ?
2009                                         one->mode : S_IFLNK));
2010                 }
2011                 else {
2012                         /* we can borrow from the file in the work tree */
2013                         temp->name = name;
2014                         if (!one->sha1_valid)
2015                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
2016                         else
2017                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
2018                         /* Even though we may sometimes borrow the
2019                          * contents from the work tree, we always want
2020                          * one->mode.  mode is trustworthy even when
2021                          * !(one->sha1_valid), as long as
2022                          * DIFF_FILE_VALID(one).
2023                          */
2024                         sprintf(temp->mode, "%06o", one->mode);
2025                 }
2026                 return;
2027         }
2028         else {
2029                 if (diff_populate_filespec(one, 0))
2030                         die("cannot read data blob for %s", one->path);
2031                 prep_temp_blob(temp, one->data, one->size,
2032                                one->sha1, one->mode);
2033         }
2034 }
2035
2036 static void remove_tempfile(void)
2037 {
2038         int i;
2039
2040         for (i = 0; i < 2; i++)
2041                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
2042                         unlink(diff_temp[i].name);
2043                         diff_temp[i].name = NULL;
2044                 }
2045 }
2046
2047 static void remove_tempfile_on_signal(int signo)
2048 {
2049         remove_tempfile();
2050         signal(SIGINT, SIG_DFL);
2051         raise(signo);
2052 }
2053
2054 /* An external diff command takes:
2055  *
2056  * diff-cmd name infile1 infile1-sha1 infile1-mode \
2057  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2058  *
2059  */
2060 static void run_external_diff(const char *pgm,
2061                               const char *name,
2062                               const char *other,
2063                               struct diff_filespec *one,
2064                               struct diff_filespec *two,
2065                               const char *xfrm_msg,
2066                               int complete_rewrite)
2067 {
2068         const char *spawn_arg[10];
2069         struct diff_tempfile *temp = diff_temp;
2070         int retval;
2071         static int atexit_asked = 0;
2072         const char *othername;
2073         const char **arg = &spawn_arg[0];
2074
2075         othername = (other? other : name);
2076         if (one && two) {
2077                 prepare_temp_file(name, &temp[0], one);
2078                 prepare_temp_file(othername, &temp[1], two);
2079                 if (! atexit_asked &&
2080                     (temp[0].name == temp[0].tmp_path ||
2081                      temp[1].name == temp[1].tmp_path)) {
2082                         atexit_asked = 1;
2083                         atexit(remove_tempfile);
2084                 }
2085                 signal(SIGINT, remove_tempfile_on_signal);
2086         }
2087
2088         if (one && two) {
2089                 *arg++ = pgm;
2090                 *arg++ = name;
2091                 *arg++ = temp[0].name;
2092                 *arg++ = temp[0].hex;
2093                 *arg++ = temp[0].mode;
2094                 *arg++ = temp[1].name;
2095                 *arg++ = temp[1].hex;
2096                 *arg++ = temp[1].mode;
2097                 if (other) {
2098                         *arg++ = other;
2099                         *arg++ = xfrm_msg;
2100                 }
2101         } else {
2102                 *arg++ = pgm;
2103                 *arg++ = name;
2104         }
2105         *arg = NULL;
2106         fflush(NULL);
2107         retval = run_command_v_opt(spawn_arg, 0);
2108         remove_tempfile();
2109         if (retval) {
2110                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
2111                 exit(1);
2112         }
2113 }
2114
2115 static const char *external_diff_attr(const char *name)
2116 {
2117         struct git_attr_check attr_diff_check;
2118
2119         if (!name)
2120                 return NULL;
2121
2122         setup_diff_attr_check(&attr_diff_check);
2123         if (!git_checkattr(name, 1, &attr_diff_check)) {
2124                 const char *value = attr_diff_check.value;
2125                 if (!ATTR_TRUE(value) &&
2126                     !ATTR_FALSE(value) &&
2127                     !ATTR_UNSET(value)) {
2128                         struct ll_diff_driver *drv;
2129
2130                         for (drv = user_diff; drv; drv = drv->next)
2131                                 if (!strcmp(drv->name, value))
2132                                         return drv->cmd;
2133                 }
2134         }
2135         return NULL;
2136 }
2137
2138 static void run_diff_cmd(const char *pgm,
2139                          const char *name,
2140                          const char *other,
2141                          const char *attr_path,
2142                          struct diff_filespec *one,
2143                          struct diff_filespec *two,
2144                          const char *xfrm_msg,
2145                          struct diff_options *o,
2146                          int complete_rewrite)
2147 {
2148         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
2149                 pgm = NULL;
2150         else {
2151                 const char *cmd = external_diff_attr(attr_path);
2152                 if (cmd)
2153                         pgm = cmd;
2154         }
2155
2156         if (pgm) {
2157                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
2158                                   complete_rewrite);
2159                 return;
2160         }
2161         if (one && two)
2162                 builtin_diff(name, other ? other : name,
2163                              one, two, xfrm_msg, o, complete_rewrite);
2164         else
2165                 fprintf(o->file, "* Unmerged path %s\n", name);
2166 }
2167
2168 static void diff_fill_sha1_info(struct diff_filespec *one)
2169 {
2170         if (DIFF_FILE_VALID(one)) {
2171                 if (!one->sha1_valid) {
2172                         struct stat st;
2173                         if (!strcmp(one->path, "-")) {
2174                                 hashcpy(one->sha1, null_sha1);
2175                                 return;
2176                         }
2177                         if (lstat(one->path, &st) < 0)
2178                                 die("stat %s", one->path);
2179                         if (index_path(one->sha1, one->path, &st, 0))
2180                                 die("cannot hash %s\n", one->path);
2181                 }
2182         }
2183         else
2184                 hashclr(one->sha1);
2185 }
2186
2187 static int similarity_index(struct diff_filepair *p)
2188 {
2189         return p->score * 100 / MAX_SCORE;
2190 }
2191
2192 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2193 {
2194         /* Strip the prefix but do not molest /dev/null and absolute paths */
2195         if (*namep && **namep != '/')
2196                 *namep += prefix_length;
2197         if (*otherp && **otherp != '/')
2198                 *otherp += prefix_length;
2199 }
2200
2201 static void run_diff(struct diff_filepair *p, struct diff_options *o)
2202 {
2203         const char *pgm = external_diff();
2204         struct strbuf msg;
2205         char *xfrm_msg;
2206         struct diff_filespec *one = p->one;
2207         struct diff_filespec *two = p->two;
2208         const char *name;
2209         const char *other;
2210         const char *attr_path;
2211         int complete_rewrite = 0;
2212
2213         name  = p->one->path;
2214         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2215         attr_path = name;
2216         if (o->prefix_length)
2217                 strip_prefix(o->prefix_length, &name, &other);
2218
2219         if (DIFF_PAIR_UNMERGED(p)) {
2220                 run_diff_cmd(pgm, name, NULL, attr_path,
2221                              NULL, NULL, NULL, o, 0);
2222                 return;
2223         }
2224
2225         diff_fill_sha1_info(one);
2226         diff_fill_sha1_info(two);
2227
2228         strbuf_init(&msg, PATH_MAX * 2 + 300);
2229         switch (p->status) {
2230         case DIFF_STATUS_COPIED:
2231                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2232                 strbuf_addstr(&msg, "\ncopy from ");
2233                 quote_c_style(name, &msg, NULL, 0);
2234                 strbuf_addstr(&msg, "\ncopy to ");
2235                 quote_c_style(other, &msg, NULL, 0);
2236                 strbuf_addch(&msg, '\n');
2237                 break;
2238         case DIFF_STATUS_RENAMED:
2239                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2240                 strbuf_addstr(&msg, "\nrename from ");
2241                 quote_c_style(name, &msg, NULL, 0);
2242                 strbuf_addstr(&msg, "\nrename to ");
2243                 quote_c_style(other, &msg, NULL, 0);
2244                 strbuf_addch(&msg, '\n');
2245                 break;
2246         case DIFF_STATUS_MODIFIED:
2247                 if (p->score) {
2248                         strbuf_addf(&msg, "dissimilarity index %d%%\n",
2249                                         similarity_index(p));
2250                         complete_rewrite = 1;
2251                         break;
2252                 }
2253                 /* fallthru */
2254         default:
2255                 /* nothing */
2256                 ;
2257         }
2258
2259         if (hashcmp(one->sha1, two->sha1)) {
2260                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2261
2262                 if (DIFF_OPT_TST(o, BINARY)) {
2263                         mmfile_t mf;
2264                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2265                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2266                                 abbrev = 40;
2267                 }
2268                 strbuf_addf(&msg, "index %.*s..%.*s",
2269                                 abbrev, sha1_to_hex(one->sha1),
2270                                 abbrev, sha1_to_hex(two->sha1));
2271                 if (one->mode == two->mode)
2272                         strbuf_addf(&msg, " %06o", one->mode);
2273                 strbuf_addch(&msg, '\n');
2274         }
2275
2276         if (msg.len)
2277                 strbuf_setlen(&msg, msg.len - 1);
2278         xfrm_msg = msg.len ? msg.buf : NULL;
2279
2280         if (!pgm &&
2281             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
2282             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
2283                 /* a filepair that changes between file and symlink
2284                  * needs to be split into deletion and creation.
2285                  */
2286                 struct diff_filespec *null = alloc_filespec(two->path);
2287                 run_diff_cmd(NULL, name, other, attr_path,
2288                              one, null, xfrm_msg, o, 0);
2289                 free(null);
2290                 null = alloc_filespec(one->path);
2291                 run_diff_cmd(NULL, name, other, attr_path,
2292                              null, two, xfrm_msg, o, 0);
2293                 free(null);
2294         }
2295         else
2296                 run_diff_cmd(pgm, name, other, attr_path,
2297                              one, two, xfrm_msg, o, complete_rewrite);
2298
2299         strbuf_release(&msg);
2300 }
2301
2302 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
2303                          struct diffstat_t *diffstat)
2304 {
2305         const char *name;
2306         const char *other;
2307         int complete_rewrite = 0;
2308
2309         if (DIFF_PAIR_UNMERGED(p)) {
2310                 /* unmerged */
2311                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
2312                 return;
2313         }
2314
2315         name = p->one->path;
2316         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2317
2318         if (o->prefix_length)
2319                 strip_prefix(o->prefix_length, &name, &other);
2320
2321         diff_fill_sha1_info(p->one);
2322         diff_fill_sha1_info(p->two);
2323
2324         if (p->status == DIFF_STATUS_MODIFIED && p->score)
2325                 complete_rewrite = 1;
2326         builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
2327 }
2328
2329 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
2330 {
2331         const char *name;
2332         const char *other;
2333         const char *attr_path;
2334
2335         if (DIFF_PAIR_UNMERGED(p)) {
2336                 /* unmerged */
2337                 return;
2338         }
2339
2340         name = p->one->path;
2341         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2342         attr_path = other ? other : name;
2343
2344         if (o->prefix_length)
2345                 strip_prefix(o->prefix_length, &name, &other);
2346
2347         diff_fill_sha1_info(p->one);
2348         diff_fill_sha1_info(p->two);
2349
2350         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
2351 }
2352
2353 void diff_setup(struct diff_options *options)
2354 {
2355         memset(options, 0, sizeof(*options));
2356
2357         options->file = stdout;
2358
2359         options->line_termination = '\n';
2360         options->break_opt = -1;
2361         options->rename_limit = -1;
2362         options->dirstat_percent = 3;
2363         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
2364         options->context = 3;
2365
2366         options->change = diff_change;
2367         options->add_remove = diff_addremove;
2368         if (diff_use_color_default > 0)
2369                 DIFF_OPT_SET(options, COLOR_DIFF);
2370         else
2371                 DIFF_OPT_CLR(options, COLOR_DIFF);
2372         options->detect_rename = diff_detect_rename_default;
2373
2374         if (!diff_mnemonic_prefix) {
2375                 options->a_prefix = "a/";
2376                 options->b_prefix = "b/";
2377         }
2378 }
2379
2380 int diff_setup_done(struct diff_options *options)
2381 {
2382         int count = 0;
2383
2384         if (options->output_format & DIFF_FORMAT_NAME)
2385                 count++;
2386         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
2387                 count++;
2388         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
2389                 count++;
2390         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
2391                 count++;
2392         if (count > 1)
2393                 die("--name-only, --name-status, --check and -s are mutually exclusive");
2394
2395         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
2396                 options->detect_rename = DIFF_DETECT_COPY;
2397
2398         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
2399                 options->prefix = NULL;
2400         if (options->prefix)
2401                 options->prefix_length = strlen(options->prefix);
2402         else
2403                 options->prefix_length = 0;
2404
2405         if (options->output_format & (DIFF_FORMAT_NAME |
2406                                       DIFF_FORMAT_NAME_STATUS |
2407                                       DIFF_FORMAT_CHECKDIFF |
2408                                       DIFF_FORMAT_NO_OUTPUT))
2409                 options->output_format &= ~(DIFF_FORMAT_RAW |
2410                                             DIFF_FORMAT_NUMSTAT |
2411                                             DIFF_FORMAT_DIFFSTAT |
2412                                             DIFF_FORMAT_SHORTSTAT |
2413                                             DIFF_FORMAT_DIRSTAT |
2414                                             DIFF_FORMAT_SUMMARY |
2415                                             DIFF_FORMAT_PATCH);
2416
2417         /*
2418          * These cases always need recursive; we do not drop caller-supplied
2419          * recursive bits for other formats here.
2420          */
2421         if (options->output_format & (DIFF_FORMAT_PATCH |
2422                                       DIFF_FORMAT_NUMSTAT |
2423                                       DIFF_FORMAT_DIFFSTAT |
2424                                       DIFF_FORMAT_SHORTSTAT |
2425                                       DIFF_FORMAT_DIRSTAT |
2426                                       DIFF_FORMAT_SUMMARY |
2427                                       DIFF_FORMAT_CHECKDIFF))
2428                 DIFF_OPT_SET(options, RECURSIVE);
2429         /*
2430          * Also pickaxe would not work very well if you do not say recursive
2431          */
2432         if (options->pickaxe)
2433                 DIFF_OPT_SET(options, RECURSIVE);
2434
2435         if (options->detect_rename && options->rename_limit < 0)
2436                 options->rename_limit = diff_rename_limit_default;
2437         if (options->setup & DIFF_SETUP_USE_CACHE) {
2438                 if (!active_cache)
2439                         /* read-cache does not die even when it fails
2440                          * so it is safe for us to do this here.  Also
2441                          * it does not smudge active_cache or active_nr
2442                          * when it fails, so we do not have to worry about
2443                          * cleaning it up ourselves either.
2444                          */
2445                         read_cache();
2446         }
2447         if (options->abbrev <= 0 || 40 < options->abbrev)
2448                 options->abbrev = 40; /* full */
2449
2450         /*
2451          * It does not make sense to show the first hit we happened
2452          * to have found.  It does not make sense not to return with
2453          * exit code in such a case either.
2454          */
2455         if (DIFF_OPT_TST(options, QUIET)) {
2456                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
2457                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2458         }
2459
2460         return 0;
2461 }
2462
2463 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
2464 {
2465         char c, *eq;
2466         int len;
2467
2468         if (*arg != '-')
2469                 return 0;
2470         c = *++arg;
2471         if (!c)
2472                 return 0;
2473         if (c == arg_short) {
2474                 c = *++arg;
2475                 if (!c)
2476                         return 1;
2477                 if (val && isdigit(c)) {
2478                         char *end;
2479                         int n = strtoul(arg, &end, 10);
2480                         if (*end)
2481                                 return 0;
2482                         *val = n;
2483                         return 1;
2484                 }
2485                 return 0;
2486         }
2487         if (c != '-')
2488                 return 0;
2489         arg++;
2490         eq = strchr(arg, '=');
2491         if (eq)
2492                 len = eq - arg;
2493         else
2494                 len = strlen(arg);
2495         if (!len || strncmp(arg, arg_long, len))
2496                 return 0;
2497         if (eq) {
2498                 int n;
2499                 char *end;
2500                 if (!isdigit(*++eq))
2501                         return 0;
2502                 n = strtoul(eq, &end, 10);
2503                 if (*end)
2504                         return 0;
2505                 *val = n;
2506         }
2507         return 1;
2508 }
2509
2510 static int diff_scoreopt_parse(const char *opt);
2511
2512 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
2513 {
2514         const char *arg = av[0];
2515
2516         /* Output format options */
2517         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
2518                 options->output_format |= DIFF_FORMAT_PATCH;
2519         else if (opt_arg(arg, 'U', "unified", &options->context))
2520                 options->output_format |= DIFF_FORMAT_PATCH;
2521         else if (!strcmp(arg, "--raw"))
2522                 options->output_format |= DIFF_FORMAT_RAW;
2523         else if (!strcmp(arg, "--patch-with-raw"))
2524                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
2525         else if (!strcmp(arg, "--numstat"))
2526                 options->output_format |= DIFF_FORMAT_NUMSTAT;
2527         else if (!strcmp(arg, "--shortstat"))
2528                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
2529         else if (opt_arg(arg, 'X', "dirstat", &options->dirstat_percent))
2530                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2531         else if (!strcmp(arg, "--cumulative")) {
2532                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2533                 DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
2534         } else if (opt_arg(arg, 0, "dirstat-by-file",
2535                            &options->dirstat_percent)) {
2536                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2537                 DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
2538         }
2539         else if (!strcmp(arg, "--check"))
2540                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
2541         else if (!strcmp(arg, "--summary"))
2542                 options->output_format |= DIFF_FORMAT_SUMMARY;
2543         else if (!strcmp(arg, "--patch-with-stat"))
2544                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
2545         else if (!strcmp(arg, "--name-only"))
2546                 options->output_format |= DIFF_FORMAT_NAME;
2547         else if (!strcmp(arg, "--name-status"))
2548                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
2549         else if (!strcmp(arg, "-s"))
2550                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
2551         else if (!prefixcmp(arg, "--stat")) {
2552                 char *end;
2553                 int width = options->stat_width;
2554                 int name_width = options->stat_name_width;
2555                 arg += 6;
2556                 end = (char *)arg;
2557
2558                 switch (*arg) {
2559                 case '-':
2560                         if (!prefixcmp(arg, "-width="))
2561                                 width = strtoul(arg + 7, &end, 10);
2562                         else if (!prefixcmp(arg, "-name-width="))
2563                                 name_width = strtoul(arg + 12, &end, 10);
2564                         break;
2565                 case '=':
2566                         width = strtoul(arg+1, &end, 10);
2567                         if (*end == ',')
2568                                 name_width = strtoul(end+1, &end, 10);
2569                 }
2570
2571                 /* Important! This checks all the error cases! */
2572                 if (*end)
2573                         return 0;
2574                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
2575                 options->stat_name_width = name_width;
2576                 options->stat_width = width;
2577         }
2578
2579         /* renames options */
2580         else if (!prefixcmp(arg, "-B")) {
2581                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
2582                         return -1;
2583         }
2584         else if (!prefixcmp(arg, "-M")) {
2585                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2586                         return -1;
2587                 options->detect_rename = DIFF_DETECT_RENAME;
2588         }
2589         else if (!prefixcmp(arg, "-C")) {
2590                 if (options->detect_rename == DIFF_DETECT_COPY)
2591                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2592                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2593                         return -1;
2594                 options->detect_rename = DIFF_DETECT_COPY;
2595         }
2596         else if (!strcmp(arg, "--no-renames"))
2597                 options->detect_rename = 0;
2598         else if (!strcmp(arg, "--relative"))
2599                 DIFF_OPT_SET(options, RELATIVE_NAME);
2600         else if (!prefixcmp(arg, "--relative=")) {
2601                 DIFF_OPT_SET(options, RELATIVE_NAME);
2602                 options->prefix = arg + 11;
2603         }
2604
2605         /* xdiff options */
2606         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
2607                 options->xdl_opts |= XDF_IGNORE_WHITESPACE;
2608         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
2609                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2610         else if (!strcmp(arg, "--ignore-space-at-eol"))
2611                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2612
2613         /* flags options */
2614         else if (!strcmp(arg, "--binary")) {
2615                 options->output_format |= DIFF_FORMAT_PATCH;
2616                 DIFF_OPT_SET(options, BINARY);
2617         }
2618         else if (!strcmp(arg, "--full-index"))
2619                 DIFF_OPT_SET(options, FULL_INDEX);
2620         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
2621                 DIFF_OPT_SET(options, TEXT);
2622         else if (!strcmp(arg, "-R"))
2623                 DIFF_OPT_SET(options, REVERSE_DIFF);
2624         else if (!strcmp(arg, "--find-copies-harder"))
2625                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2626         else if (!strcmp(arg, "--follow"))
2627                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
2628         else if (!strcmp(arg, "--color"))
2629                 DIFF_OPT_SET(options, COLOR_DIFF);
2630         else if (!strcmp(arg, "--no-color"))
2631                 DIFF_OPT_CLR(options, COLOR_DIFF);
2632         else if (!strcmp(arg, "--color-words"))
2633                 options->flags |= DIFF_OPT_COLOR_DIFF | DIFF_OPT_COLOR_DIFF_WORDS;
2634         else if (!strcmp(arg, "--exit-code"))
2635                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2636         else if (!strcmp(arg, "--quiet"))
2637                 DIFF_OPT_SET(options, QUIET);
2638         else if (!strcmp(arg, "--ext-diff"))
2639                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
2640         else if (!strcmp(arg, "--no-ext-diff"))
2641                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
2642         else if (!strcmp(arg, "--ignore-submodules"))
2643                 DIFF_OPT_SET(options, IGNORE_SUBMODULES);
2644
2645         /* misc options */
2646         else if (!strcmp(arg, "-z"))
2647                 options->line_termination = 0;
2648         else if (!prefixcmp(arg, "-l"))
2649                 options->rename_limit = strtoul(arg+2, NULL, 10);
2650         else if (!prefixcmp(arg, "-S"))
2651                 options->pickaxe = arg + 2;
2652         else if (!strcmp(arg, "--pickaxe-all"))
2653                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
2654         else if (!strcmp(arg, "--pickaxe-regex"))
2655                 options->pickaxe_opts = DIFF_PICKAXE_REGEX;
2656         else if (!prefixcmp(arg, "-O"))
2657                 options->orderfile = arg + 2;
2658         else if (!prefixcmp(arg, "--diff-filter="))
2659                 options->filter = arg + 14;
2660         else if (!strcmp(arg, "--abbrev"))
2661                 options->abbrev = DEFAULT_ABBREV;
2662         else if (!prefixcmp(arg, "--abbrev=")) {
2663                 options->abbrev = strtoul(arg + 9, NULL, 10);
2664                 if (options->abbrev < MINIMUM_ABBREV)
2665                         options->abbrev = MINIMUM_ABBREV;
2666                 else if (40 < options->abbrev)
2667                         options->abbrev = 40;
2668         }
2669         else if (!prefixcmp(arg, "--src-prefix="))
2670                 options->a_prefix = arg + 13;
2671         else if (!prefixcmp(arg, "--dst-prefix="))
2672                 options->b_prefix = arg + 13;
2673         else if (!strcmp(arg, "--no-prefix"))
2674                 options->a_prefix = options->b_prefix = "";
2675         else if (!prefixcmp(arg, "--output=")) {
2676                 options->file = fopen(arg + strlen("--output="), "w");
2677                 options->close_file = 1;
2678         } else
2679                 return 0;
2680         return 1;
2681 }
2682
2683 static int parse_num(const char **cp_p)
2684 {
2685         unsigned long num, scale;
2686         int ch, dot;
2687         const char *cp = *cp_p;
2688
2689         num = 0;
2690         scale = 1;
2691         dot = 0;
2692         for(;;) {
2693                 ch = *cp;
2694                 if ( !dot && ch == '.' ) {
2695                         scale = 1;
2696                         dot = 1;
2697                 } else if ( ch == '%' ) {
2698                         scale = dot ? scale*100 : 100;
2699                         cp++;   /* % is always at the end */
2700                         break;
2701                 } else if ( ch >= '0' && ch <= '9' ) {
2702                         if ( scale < 100000 ) {
2703                                 scale *= 10;
2704                                 num = (num*10) + (ch-'0');
2705                         }
2706                 } else {
2707                         break;
2708                 }
2709                 cp++;
2710         }
2711         *cp_p = cp;
2712
2713         /* user says num divided by scale and we say internally that
2714          * is MAX_SCORE * num / scale.
2715          */
2716         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
2717 }
2718
2719 static int diff_scoreopt_parse(const char *opt)
2720 {
2721         int opt1, opt2, cmd;
2722
2723         if (*opt++ != '-')
2724                 return -1;
2725         cmd = *opt++;
2726         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
2727                 return -1; /* that is not a -M, -C nor -B option */
2728
2729         opt1 = parse_num(&opt);
2730         if (cmd != 'B')
2731                 opt2 = 0;
2732         else {
2733                 if (*opt == 0)
2734                         opt2 = 0;
2735                 else if (*opt != '/')
2736                         return -1; /* we expect -B80/99 or -B80 */
2737                 else {
2738                         opt++;
2739                         opt2 = parse_num(&opt);
2740                 }
2741         }
2742         if (*opt != 0)
2743                 return -1;
2744         return opt1 | (opt2 << 16);
2745 }
2746
2747 struct diff_queue_struct diff_queued_diff;
2748
2749 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
2750 {
2751         if (queue->alloc <= queue->nr) {
2752                 queue->alloc = alloc_nr(queue->alloc);
2753                 queue->queue = xrealloc(queue->queue,
2754                                         sizeof(dp) * queue->alloc);
2755         }
2756         queue->queue[queue->nr++] = dp;
2757 }
2758
2759 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
2760                                  struct diff_filespec *one,
2761                                  struct diff_filespec *two)
2762 {
2763         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
2764         dp->one = one;
2765         dp->two = two;
2766         if (queue)
2767                 diff_q(queue, dp);
2768         return dp;
2769 }
2770
2771 void diff_free_filepair(struct diff_filepair *p)
2772 {
2773         free_filespec(p->one);
2774         free_filespec(p->two);
2775         free(p);
2776 }
2777
2778 /* This is different from find_unique_abbrev() in that
2779  * it stuffs the result with dots for alignment.
2780  */
2781 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
2782 {
2783         int abblen;
2784         const char *abbrev;
2785         if (len == 40)
2786                 return sha1_to_hex(sha1);
2787
2788         abbrev = find_unique_abbrev(sha1, len);
2789         abblen = strlen(abbrev);
2790         if (abblen < 37) {
2791                 static char hex[41];
2792                 if (len < abblen && abblen <= len + 2)
2793                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
2794                 else
2795                         sprintf(hex, "%s...", abbrev);
2796                 return hex;
2797         }
2798         return sha1_to_hex(sha1);
2799 }
2800
2801 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
2802 {
2803         int line_termination = opt->line_termination;
2804         int inter_name_termination = line_termination ? '\t' : '\0';
2805
2806         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
2807                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
2808                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
2809                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
2810         }
2811         if (p->score) {
2812                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
2813                         inter_name_termination);
2814         } else {
2815                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
2816         }
2817
2818         if (p->status == DIFF_STATUS_COPIED ||
2819             p->status == DIFF_STATUS_RENAMED) {
2820                 const char *name_a, *name_b;
2821                 name_a = p->one->path;
2822                 name_b = p->two->path;
2823                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2824                 write_name_quoted(name_a, opt->file, inter_name_termination);
2825                 write_name_quoted(name_b, opt->file, line_termination);
2826         } else {
2827                 const char *name_a, *name_b;
2828                 name_a = p->one->mode ? p->one->path : p->two->path;
2829                 name_b = NULL;
2830                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2831                 write_name_quoted(name_a, opt->file, line_termination);
2832         }
2833 }
2834
2835 int diff_unmodified_pair(struct diff_filepair *p)
2836 {
2837         /* This function is written stricter than necessary to support
2838          * the currently implemented transformers, but the idea is to
2839          * let transformers to produce diff_filepairs any way they want,
2840          * and filter and clean them up here before producing the output.
2841          */
2842         struct diff_filespec *one = p->one, *two = p->two;
2843
2844         if (DIFF_PAIR_UNMERGED(p))
2845                 return 0; /* unmerged is interesting */
2846
2847         /* deletion, addition, mode or type change
2848          * and rename are all interesting.
2849          */
2850         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
2851             DIFF_PAIR_MODE_CHANGED(p) ||
2852             strcmp(one->path, two->path))
2853                 return 0;
2854
2855         /* both are valid and point at the same path.  that is, we are
2856          * dealing with a change.
2857          */
2858         if (one->sha1_valid && two->sha1_valid &&
2859             !hashcmp(one->sha1, two->sha1))
2860                 return 1; /* no change */
2861         if (!one->sha1_valid && !two->sha1_valid)
2862                 return 1; /* both look at the same file on the filesystem. */
2863         return 0;
2864 }
2865
2866 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
2867 {
2868         if (diff_unmodified_pair(p))
2869                 return;
2870
2871         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2872             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2873                 return; /* no tree diffs in patch format */
2874
2875         run_diff(p, o);
2876 }
2877
2878 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
2879                             struct diffstat_t *diffstat)
2880 {
2881         if (diff_unmodified_pair(p))
2882                 return;
2883
2884         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2885             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2886                 return; /* no tree diffs in patch format */
2887
2888         run_diffstat(p, o, diffstat);
2889 }
2890
2891 static void diff_flush_checkdiff(struct diff_filepair *p,
2892                 struct diff_options *o)
2893 {
2894         if (diff_unmodified_pair(p))
2895                 return;
2896
2897         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2898             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2899                 return; /* no tree diffs in patch format */
2900
2901         run_checkdiff(p, o);
2902 }
2903
2904 int diff_queue_is_empty(void)
2905 {
2906         struct diff_queue_struct *q = &diff_queued_diff;
2907         int i;
2908         for (i = 0; i < q->nr; i++)
2909                 if (!diff_unmodified_pair(q->queue[i]))
2910                         return 0;
2911         return 1;
2912 }
2913
2914 #if DIFF_DEBUG
2915 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
2916 {
2917         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
2918                 x, one ? one : "",
2919                 s->path,
2920                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
2921                 s->mode,
2922                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
2923         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
2924                 x, one ? one : "",
2925                 s->size, s->xfrm_flags);
2926 }
2927
2928 void diff_debug_filepair(const struct diff_filepair *p, int i)
2929 {
2930         diff_debug_filespec(p->one, i, "one");
2931         diff_debug_filespec(p->two, i, "two");
2932         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
2933                 p->score, p->status ? p->status : '?',
2934                 p->one->rename_used, p->broken_pair);
2935 }
2936
2937 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
2938 {
2939         int i;
2940         if (msg)
2941                 fprintf(stderr, "%s\n", msg);
2942         fprintf(stderr, "q->nr = %d\n", q->nr);
2943         for (i = 0; i < q->nr; i++) {
2944                 struct diff_filepair *p = q->queue[i];
2945                 diff_debug_filepair(p, i);
2946         }
2947 }
2948 #endif
2949
2950 static void diff_resolve_rename_copy(void)
2951 {
2952         int i;
2953         struct diff_filepair *p;
2954         struct diff_queue_struct *q = &diff_queued_diff;
2955
2956         diff_debug_queue("resolve-rename-copy", q);
2957
2958         for (i = 0; i < q->nr; i++) {
2959                 p = q->queue[i];
2960                 p->status = 0; /* undecided */
2961                 if (DIFF_PAIR_UNMERGED(p))
2962                         p->status = DIFF_STATUS_UNMERGED;
2963                 else if (!DIFF_FILE_VALID(p->one))
2964                         p->status = DIFF_STATUS_ADDED;
2965                 else if (!DIFF_FILE_VALID(p->two))
2966                         p->status = DIFF_STATUS_DELETED;
2967                 else if (DIFF_PAIR_TYPE_CHANGED(p))
2968                         p->status = DIFF_STATUS_TYPE_CHANGED;
2969
2970                 /* from this point on, we are dealing with a pair
2971                  * whose both sides are valid and of the same type, i.e.
2972                  * either in-place edit or rename/copy edit.
2973                  */
2974                 else if (DIFF_PAIR_RENAME(p)) {
2975                         /*
2976                          * A rename might have re-connected a broken
2977                          * pair up, causing the pathnames to be the
2978                          * same again. If so, that's not a rename at
2979                          * all, just a modification..
2980                          *
2981                          * Otherwise, see if this source was used for
2982                          * multiple renames, in which case we decrement
2983                          * the count, and call it a copy.
2984                          */
2985                         if (!strcmp(p->one->path, p->two->path))
2986                                 p->status = DIFF_STATUS_MODIFIED;
2987                         else if (--p->one->rename_used > 0)
2988                                 p->status = DIFF_STATUS_COPIED;
2989                         else
2990                                 p->status = DIFF_STATUS_RENAMED;
2991                 }
2992                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
2993                          p->one->mode != p->two->mode ||
2994                          is_null_sha1(p->one->sha1))
2995                         p->status = DIFF_STATUS_MODIFIED;
2996                 else {
2997                         /* This is a "no-change" entry and should not
2998                          * happen anymore, but prepare for broken callers.
2999                          */
3000                         error("feeding unmodified %s to diffcore",
3001                               p->one->path);
3002                         p->status = DIFF_STATUS_UNKNOWN;
3003                 }
3004         }
3005         diff_debug_queue("resolve-rename-copy done", q);
3006 }
3007
3008 static int check_pair_status(struct diff_filepair *p)
3009 {
3010         switch (p->status) {
3011         case DIFF_STATUS_UNKNOWN:
3012                 return 0;
3013         case 0:
3014                 die("internal error in diff-resolve-rename-copy");
3015         default:
3016                 return 1;
3017         }
3018 }
3019
3020 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
3021 {
3022         int fmt = opt->output_format;
3023
3024         if (fmt & DIFF_FORMAT_CHECKDIFF)
3025                 diff_flush_checkdiff(p, opt);
3026         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
3027                 diff_flush_raw(p, opt);
3028         else if (fmt & DIFF_FORMAT_NAME) {
3029                 const char *name_a, *name_b;
3030                 name_a = p->two->path;
3031                 name_b = NULL;
3032                 strip_prefix(opt->prefix_length, &name_a, &name_b);
3033                 write_name_quoted(name_a, opt->file, opt->line_termination);
3034         }
3035 }
3036
3037 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
3038 {
3039         if (fs->mode)
3040                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
3041         else
3042                 fprintf(file, " %s ", newdelete);
3043         write_name_quoted(fs->path, file, '\n');
3044 }
3045
3046
3047 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name)
3048 {
3049         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
3050                 fprintf(file, " mode change %06o => %06o%c", p->one->mode, p->two->mode,
3051                         show_name ? ' ' : '\n');
3052                 if (show_name) {
3053                         write_name_quoted(p->two->path, file, '\n');
3054                 }
3055         }
3056 }
3057
3058 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p)
3059 {
3060         char *names = pprint_rename(p->one->path, p->two->path);
3061
3062         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
3063         free(names);
3064         show_mode_change(file, p, 0);
3065 }
3066
3067 static void diff_summary(FILE *file, struct diff_filepair *p)
3068 {
3069         switch(p->status) {
3070         case DIFF_STATUS_DELETED:
3071                 show_file_mode_name(file, "delete", p->one);
3072                 break;
3073         case DIFF_STATUS_ADDED:
3074                 show_file_mode_name(file, "create", p->two);
3075                 break;
3076         case DIFF_STATUS_COPIED:
3077                 show_rename_copy(file, "copy", p);
3078                 break;
3079         case DIFF_STATUS_RENAMED:
3080                 show_rename_copy(file, "rename", p);
3081                 break;
3082         default:
3083                 if (p->score) {
3084                         fputs(" rewrite ", file);
3085                         write_name_quoted(p->two->path, file, ' ');
3086                         fprintf(file, "(%d%%)\n", similarity_index(p));
3087                 }
3088                 show_mode_change(file, p, !p->score);
3089                 break;
3090         }
3091 }
3092
3093 struct patch_id_t {
3094         git_SHA_CTX *ctx;
3095         int patchlen;
3096 };
3097
3098 static int remove_space(char *line, int len)
3099 {
3100         int i;
3101         char *dst = line;
3102         unsigned char c;
3103
3104         for (i = 0; i < len; i++)
3105                 if (!isspace((c = line[i])))
3106                         *dst++ = c;
3107
3108         return dst - line;
3109 }
3110
3111 static void patch_id_consume(void *priv, char *line, unsigned long len)
3112 {
3113         struct patch_id_t *data = priv;
3114         int new_len;
3115
3116         /* Ignore line numbers when computing the SHA1 of the patch */
3117         if (!prefixcmp(line, "@@ -"))
3118                 return;
3119
3120         new_len = remove_space(line, len);
3121
3122         git_SHA1_Update(data->ctx, line, new_len);
3123         data->patchlen += new_len;
3124 }
3125
3126 /* returns 0 upon success, and writes result into sha1 */
3127 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
3128 {
3129         struct diff_queue_struct *q = &diff_queued_diff;
3130         int i;
3131         git_SHA_CTX ctx;
3132         struct patch_id_t data;
3133         char buffer[PATH_MAX * 4 + 20];
3134
3135         git_SHA1_Init(&ctx);
3136         memset(&data, 0, sizeof(struct patch_id_t));
3137         data.ctx = &ctx;
3138
3139         for (i = 0; i < q->nr; i++) {
3140                 xpparam_t xpp;
3141                 xdemitconf_t xecfg;
3142                 xdemitcb_t ecb;
3143                 mmfile_t mf1, mf2;
3144                 struct diff_filepair *p = q->queue[i];
3145                 int len1, len2;
3146
3147                 memset(&xecfg, 0, sizeof(xecfg));
3148                 if (p->status == 0)
3149                         return error("internal diff status error");
3150                 if (p->status == DIFF_STATUS_UNKNOWN)
3151                         continue;
3152                 if (diff_unmodified_pair(p))
3153                         continue;
3154                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3155                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3156                         continue;
3157                 if (DIFF_PAIR_UNMERGED(p))
3158                         continue;
3159
3160                 diff_fill_sha1_info(p->one);
3161                 diff_fill_sha1_info(p->two);
3162                 if (fill_mmfile(&mf1, p->one) < 0 ||
3163                                 fill_mmfile(&mf2, p->two) < 0)
3164                         return error("unable to read files to diff");
3165
3166                 len1 = remove_space(p->one->path, strlen(p->one->path));
3167                 len2 = remove_space(p->two->path, strlen(p->two->path));
3168                 if (p->one->mode == 0)
3169                         len1 = snprintf(buffer, sizeof(buffer),
3170                                         "diff--gita/%.*sb/%.*s"
3171                                         "newfilemode%06o"
3172                                         "---/dev/null"
3173                                         "+++b/%.*s",
3174                                         len1, p->one->path,
3175                                         len2, p->two->path,
3176                                         p->two->mode,
3177                                         len2, p->two->path);
3178                 else if (p->two->mode == 0)
3179                         len1 = snprintf(buffer, sizeof(buffer),
3180                                         "diff--gita/%.*sb/%.*s"
3181                                         "deletedfilemode%06o"
3182                                         "---a/%.*s"
3183                                         "+++/dev/null",
3184                                         len1, p->one->path,
3185                                         len2, p->two->path,
3186                                         p->one->mode,
3187                                         len1, p->one->path);
3188                 else
3189                         len1 = snprintf(buffer, sizeof(buffer),
3190                                         "diff--gita/%.*sb/%.*s"
3191                                         "---a/%.*s"
3192                                         "+++b/%.*s",
3193                                         len1, p->one->path,
3194                                         len2, p->two->path,
3195                                         len1, p->one->path,
3196                                         len2, p->two->path);
3197                 git_SHA1_Update(&ctx, buffer, len1);
3198
3199                 xpp.flags = XDF_NEED_MINIMAL;
3200                 xecfg.ctxlen = 3;
3201                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3202                 xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
3203                               &xpp, &xecfg, &ecb);
3204         }
3205
3206         git_SHA1_Final(sha1, &ctx);
3207         return 0;
3208 }
3209
3210 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
3211 {
3212         struct diff_queue_struct *q = &diff_queued_diff;
3213         int i;
3214         int result = diff_get_patch_id(options, sha1);
3215
3216         for (i = 0; i < q->nr; i++)
3217                 diff_free_filepair(q->queue[i]);
3218
3219         free(q->queue);
3220         q->queue = NULL;
3221         q->nr = q->alloc = 0;
3222
3223         return result;
3224 }
3225
3226 static int is_summary_empty(const struct diff_queue_struct *q)
3227 {
3228         int i;
3229
3230         for (i = 0; i < q->nr; i++) {
3231                 const struct diff_filepair *p = q->queue[i];
3232
3233                 switch (p->status) {
3234                 case DIFF_STATUS_DELETED:
3235                 case DIFF_STATUS_ADDED:
3236                 case DIFF_STATUS_COPIED:
3237                 case DIFF_STATUS_RENAMED:
3238                         return 0;
3239                 default:
3240                         if (p->score)
3241                                 return 0;
3242                         if (p->one->mode && p->two->mode &&
3243                             p->one->mode != p->two->mode)
3244                                 return 0;
3245                         break;
3246                 }
3247         }
3248         return 1;
3249 }
3250
3251 void diff_flush(struct diff_options *options)
3252 {
3253         struct diff_queue_struct *q = &diff_queued_diff;
3254         int i, output_format = options->output_format;
3255         int separator = 0;
3256
3257         /*
3258          * Order: raw, stat, summary, patch
3259          * or:    name/name-status/checkdiff (other bits clear)
3260          */
3261         if (!q->nr)
3262                 goto free_queue;
3263
3264         if (output_format & (DIFF_FORMAT_RAW |
3265                              DIFF_FORMAT_NAME |
3266                              DIFF_FORMAT_NAME_STATUS |
3267                              DIFF_FORMAT_CHECKDIFF)) {
3268                 for (i = 0; i < q->nr; i++) {
3269                         struct diff_filepair *p = q->queue[i];
3270                         if (check_pair_status(p))
3271                                 flush_one_pair(p, options);
3272                 }
3273                 separator++;
3274         }
3275
3276         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT)) {
3277                 struct diffstat_t diffstat;
3278
3279                 memset(&diffstat, 0, sizeof(struct diffstat_t));
3280                 for (i = 0; i < q->nr; i++) {
3281                         struct diff_filepair *p = q->queue[i];
3282                         if (check_pair_status(p))
3283                                 diff_flush_stat(p, options, &diffstat);
3284                 }
3285                 if (output_format & DIFF_FORMAT_NUMSTAT)
3286                         show_numstat(&diffstat, options);
3287                 if (output_format & DIFF_FORMAT_DIFFSTAT)
3288                         show_stats(&diffstat, options);
3289                 if (output_format & DIFF_FORMAT_SHORTSTAT)
3290                         show_shortstats(&diffstat, options);
3291                 free_diffstat_info(&diffstat);
3292                 separator++;
3293         }
3294         if (output_format & DIFF_FORMAT_DIRSTAT)
3295                 show_dirstat(options);
3296
3297         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
3298                 for (i = 0; i < q->nr; i++)
3299                         diff_summary(options->file, q->queue[i]);
3300                 separator++;
3301         }
3302
3303         if (output_format & DIFF_FORMAT_PATCH) {
3304                 if (separator) {
3305                         putc(options->line_termination, options->file);
3306                         if (options->stat_sep) {
3307                                 /* attach patch instead of inline */
3308                                 fputs(options->stat_sep, options->file);
3309                         }
3310                 }
3311
3312                 for (i = 0; i < q->nr; i++) {
3313                         struct diff_filepair *p = q->queue[i];
3314                         if (check_pair_status(p))
3315                                 diff_flush_patch(p, options);
3316                 }
3317         }
3318
3319         if (output_format & DIFF_FORMAT_CALLBACK)
3320                 options->format_callback(q, options, options->format_callback_data);
3321
3322         for (i = 0; i < q->nr; i++)
3323                 diff_free_filepair(q->queue[i]);
3324 free_queue:
3325         free(q->queue);
3326         q->queue = NULL;
3327         q->nr = q->alloc = 0;
3328         if (options->close_file)
3329                 fclose(options->file);
3330 }
3331
3332 static void diffcore_apply_filter(const char *filter)
3333 {
3334         int i;
3335         struct diff_queue_struct *q = &diff_queued_diff;
3336         struct diff_queue_struct outq;
3337         outq.queue = NULL;
3338         outq.nr = outq.alloc = 0;
3339
3340         if (!filter)
3341                 return;
3342
3343         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
3344                 int found;
3345                 for (i = found = 0; !found && i < q->nr; i++) {
3346                         struct diff_filepair *p = q->queue[i];
3347                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3348                              ((p->score &&
3349                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3350                               (!p->score &&
3351                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3352                             ((p->status != DIFF_STATUS_MODIFIED) &&
3353                              strchr(filter, p->status)))
3354                                 found++;
3355                 }
3356                 if (found)
3357                         return;
3358
3359                 /* otherwise we will clear the whole queue
3360                  * by copying the empty outq at the end of this
3361                  * function, but first clear the current entries
3362                  * in the queue.
3363                  */
3364                 for (i = 0; i < q->nr; i++)
3365                         diff_free_filepair(q->queue[i]);
3366         }
3367         else {
3368                 /* Only the matching ones */
3369                 for (i = 0; i < q->nr; i++) {
3370                         struct diff_filepair *p = q->queue[i];
3371
3372                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3373                              ((p->score &&
3374                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3375                               (!p->score &&
3376                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3377                             ((p->status != DIFF_STATUS_MODIFIED) &&
3378                              strchr(filter, p->status)))
3379                                 diff_q(&outq, p);
3380                         else
3381                                 diff_free_filepair(p);
3382                 }
3383         }
3384         free(q->queue);
3385         *q = outq;
3386 }
3387
3388 /* Check whether two filespecs with the same mode and size are identical */
3389 static int diff_filespec_is_identical(struct diff_filespec *one,
3390                                       struct diff_filespec *two)
3391 {
3392         if (S_ISGITLINK(one->mode))
3393                 return 0;
3394         if (diff_populate_filespec(one, 0))
3395                 return 0;
3396         if (diff_populate_filespec(two, 0))
3397                 return 0;
3398         return !memcmp(one->data, two->data, one->size);
3399 }
3400
3401 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
3402 {
3403         int i;
3404         struct diff_queue_struct *q = &diff_queued_diff;
3405         struct diff_queue_struct outq;
3406         outq.queue = NULL;
3407         outq.nr = outq.alloc = 0;
3408
3409         for (i = 0; i < q->nr; i++) {
3410                 struct diff_filepair *p = q->queue[i];
3411
3412                 /*
3413                  * 1. Entries that come from stat info dirtyness
3414                  *    always have both sides (iow, not create/delete),
3415                  *    one side of the object name is unknown, with
3416                  *    the same mode and size.  Keep the ones that
3417                  *    do not match these criteria.  They have real
3418                  *    differences.
3419                  *
3420                  * 2. At this point, the file is known to be modified,
3421                  *    with the same mode and size, and the object
3422                  *    name of one side is unknown.  Need to inspect
3423                  *    the identical contents.
3424                  */
3425                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
3426                     !DIFF_FILE_VALID(p->two) ||
3427                     (p->one->sha1_valid && p->two->sha1_valid) ||
3428                     (p->one->mode != p->two->mode) ||
3429                     diff_populate_filespec(p->one, 1) ||
3430                     diff_populate_filespec(p->two, 1) ||
3431                     (p->one->size != p->two->size) ||
3432                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
3433                         diff_q(&outq, p);
3434                 else {
3435                         /*
3436                          * The caller can subtract 1 from skip_stat_unmatch
3437                          * to determine how many paths were dirty only
3438                          * due to stat info mismatch.
3439                          */
3440                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
3441                                 diffopt->skip_stat_unmatch++;
3442                         diff_free_filepair(p);
3443                 }
3444         }
3445         free(q->queue);
3446         *q = outq;
3447 }
3448
3449 void diffcore_std(struct diff_options *options)
3450 {
3451         if (options->skip_stat_unmatch)
3452                 diffcore_skip_stat_unmatch(options);
3453         if (options->break_opt != -1)
3454                 diffcore_break(options->break_opt);
3455         if (options->detect_rename)
3456                 diffcore_rename(options);
3457         if (options->break_opt != -1)
3458                 diffcore_merge_broken();
3459         if (options->pickaxe)
3460                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
3461         if (options->orderfile)
3462                 diffcore_order(options->orderfile);
3463         diff_resolve_rename_copy();
3464         diffcore_apply_filter(options->filter);
3465
3466         if (diff_queued_diff.nr)
3467                 DIFF_OPT_SET(options, HAS_CHANGES);
3468         else
3469                 DIFF_OPT_CLR(options, HAS_CHANGES);
3470 }
3471
3472 int diff_result_code(struct diff_options *opt, int status)
3473 {
3474         int result = 0;
3475         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3476             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
3477                 return status;
3478         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3479             DIFF_OPT_TST(opt, HAS_CHANGES))
3480                 result |= 01;
3481         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
3482             DIFF_OPT_TST(opt, CHECK_FAILED))
3483                 result |= 02;
3484         return result;
3485 }
3486
3487 void diff_addremove(struct diff_options *options,
3488                     int addremove, unsigned mode,
3489                     const unsigned char *sha1,
3490                     const char *concatpath)
3491 {
3492         struct diff_filespec *one, *two;
3493
3494         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(mode))
3495                 return;
3496
3497         /* This may look odd, but it is a preparation for
3498          * feeding "there are unchanged files which should
3499          * not produce diffs, but when you are doing copy
3500          * detection you would need them, so here they are"
3501          * entries to the diff-core.  They will be prefixed
3502          * with something like '=' or '*' (I haven't decided
3503          * which but should not make any difference).
3504          * Feeding the same new and old to diff_change()
3505          * also has the same effect.
3506          * Before the final output happens, they are pruned after
3507          * merged into rename/copy pairs as appropriate.
3508          */
3509         if (DIFF_OPT_TST(options, REVERSE_DIFF))
3510                 addremove = (addremove == '+' ? '-' :
3511                              addremove == '-' ? '+' : addremove);
3512
3513         if (options->prefix &&
3514             strncmp(concatpath, options->prefix, options->prefix_length))
3515                 return;
3516
3517         one = alloc_filespec(concatpath);
3518         two = alloc_filespec(concatpath);
3519
3520         if (addremove != '+')
3521                 fill_filespec(one, sha1, mode);
3522         if (addremove != '-')
3523                 fill_filespec(two, sha1, mode);
3524
3525         diff_queue(&diff_queued_diff, one, two);
3526         DIFF_OPT_SET(options, HAS_CHANGES);
3527 }
3528
3529 void diff_change(struct diff_options *options,
3530                  unsigned old_mode, unsigned new_mode,
3531                  const unsigned char *old_sha1,
3532                  const unsigned char *new_sha1,
3533                  const char *concatpath)
3534 {
3535         struct diff_filespec *one, *two;
3536
3537         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(old_mode)
3538                         && S_ISGITLINK(new_mode))
3539                 return;
3540
3541         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
3542                 unsigned tmp;
3543                 const unsigned char *tmp_c;
3544                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
3545                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
3546         }
3547
3548         if (options->prefix &&
3549             strncmp(concatpath, options->prefix, options->prefix_length))
3550                 return;
3551
3552         one = alloc_filespec(concatpath);
3553         two = alloc_filespec(concatpath);
3554         fill_filespec(one, old_sha1, old_mode);
3555         fill_filespec(two, new_sha1, new_mode);
3556
3557         diff_queue(&diff_queued_diff, one, two);
3558         DIFF_OPT_SET(options, HAS_CHANGES);
3559 }
3560
3561 void diff_unmerge(struct diff_options *options,
3562                   const char *path,
3563                   unsigned mode, const unsigned char *sha1)
3564 {
3565         struct diff_filespec *one, *two;
3566
3567         if (options->prefix &&
3568             strncmp(path, options->prefix, options->prefix_length))
3569                 return;
3570
3571         one = alloc_filespec(path);
3572         two = alloc_filespec(path);
3573         fill_filespec(one, sha1, mode);
3574         diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
3575 }